SUNGAI BESAR (THE STAR/ASIA NEWS NETWORK/BLOOMBERG) - After 12 days of campaigning, 42,365 people in Sungai Besar in Selangor state and 32,632 in Kuala Kangsar in the northern Perak region will pick new lawmakers on Saturday (June 18) after a helicopter crash last month killed incumbents from Prime Minister Najib Razak's Barisan Nasional (BN) coalition.

The vote is the first test of public support for Datuk Seri Najib on peninsular Malaysia after a year of political turmoil over funding scandals. Losses or narrower victories could spur concern in ruling party Umno about his ability to steer it to another win in a national election due by 2018. Equally, a strong win for seats already held by Umno would bolster his grip.

The by-election in Sungai Besar will see a three-way fight between (BN's) Mr Budiman Mohd Zohdi, who is also a Sungai Panjang assemblyman, Parti Islam SeMalaysia's (PAS') Dr Abdul Rani Osman, who is also a Meru assemblyman, and Parti Amanah Negara's Mr Azhar Abdul Shukur.

When the polling closes at 5pm, all the ballot boxes would be brought to the tallying centre at Dewan Seri Bernam and the results would be known as early as 9pm on the same day.

The Election Commission has targeted an at least 75 per cent voter turnout, compared with 88 per cent in the previous General Election.

The federal seat of Sungai Besar in Selangor has 42,655 registered voters that consist of 42,365 normal voters, 286 early voters and four absentee voters.

Early voting took place on June 14, and 92.6 per cent or 265 voters cast their ballots.

The by-election was held following the death of its member of Parliament Noriah Kasnon in a helicopter crash near Sebuyau, Sarawak on May 5 ahead of the state election.

Simultaneously in Kuala Kangsar, in Perak state, another by-election vote is underway.

A total of 32,632 of the 32,949 voters in the Kuala Kangsar parliamentary constituency are eligible to vote, according to the Election Commission.

The turnout in the last general election, in 2013, was 84.3 per cent in Kuala Kangsar, Perak.

The Kuala Kangsar by-election is being held simultaneously with the Sungai Besar by-election following the death of its MP, Datuk Wan Mohammad Khair-il Annuar Wan Ahmad, on May 5.

The Kuala Kangsar by-election is a four-cornered contest among Datin Mastura Mohd Yazid of BN, Dr Najihatussalehah Ahmad of PAS, Prof Ahmad Termizi Ramli of Amanah and Independent candidate Izat Bukhary Ismail Bukhary.

Of the four candidates, only Ms Mastura, who is the wife Mr Wan Mohammad, is registered as a voter in Kuala Kangsar.

Dr Najihatussalehah is a voter in Parit, Perak; Dr Ahmad Termizi, Shah Alam, Selangor; and Izat Bukhary, Kelantan.

Ms Mastura made her first public appearance in weeks when she voted at the SK Raja Perempuan Muzwin.

The wife of late Kuala Kangsar MP arrived at the school to vote at 8.30am and completed her polling at 8.45am.

During the two-week campaign, she did not leave of her residence in Kuala Kangsar because she was on her iddah (period of mourning) due to her husband's death.

The school is the voting centre for the Bukit Chandan polling district, which has 2764 registered voters.

Ms Mastura was seen chatting amiably with voters at the centre.

Hundreds of supporters from all three parties were seen at the school, but BN supporters ramped up the atmosphere when they cheered during the arrival of Ms Mastura.

Former leader Mahathir Mohamad has recently lost traction in his bid to convince party officials that Mr Najib is a liability and will cost them a reign unbroken since 1957. Most Umno divisional chiefs back the Premier, even amid concerns about slowing growth and its impact on ethnic Malays, the cornerstone of the party.

Convincing wins would help Mr Najib silence the Mahathir-led murmurings about his leadership.

"Najib desperately needs these wins," said Dr Ahmad Martadha Mohamed, dean of the college of law, government and international studies at Universiti Utara Malaysia. "It will validate his position that despite all the problems he's facing, they are able to win. Otherwise, his status will be in the balance, especially as president of Umno."

Ruling coalition BN secured a bigger majority in recent elections in Malaysia's biggest state of Sarawak, but a vote across the South China Sea on Borneo island was dominated by local issues.

Voters on the peninsula may be more attuned to the turmoil surrounding the Premier. Mr Najib, 62, has battled graft accusations since July and denied wrongdoing.

Ministers in Mr Najib's Cabinet have made daily trips to the two constituencies, shaking hands and at times handing out bags of rice and other aid to the poor. They are seeking to counter an opposition focusing on questions about Mr Najib's credibility.

In a Twitter post on Friday, Mr Najib told voters not to taken in by what he called the opposition's games.

"I support the opposition more than BN, but you have to also think about who has better access to the government, who can get more things done and who can improve your life," said Mei, an ethnic Chinese fruit seller in Sekinchan town in Sungai Besar who would give only a partial name. "You have to look out for your own interests, and not what the prime minister did or didn't do."

A divided opposition may make it easier for BN coalition to win, and the presence of multiple candidates may assist it. Two opposition groups are running against Umno for both seats, while an independent candidate has turned Kuala Kangsar into a four-cornered battle. Umno won Sungai Besar in 2013 in a straight fight, and Kuala Kangsar in a three-way race, both by narrow margins.

Race, Religion Racial and religious issues are coming to the fore of Malaysian politics, including the past two weeks of campaigning.

Umno, in power since independence, won the 2013 ballot by its slimmest-ever result as Chinese and Indian electors deserted Mr Najib's coalition.

Since then, Mr Najib has moved to woo the Malay majority. He has reached out to the opposition PAS and proposed they work to promote Islam's doctrines. PAS, which is pushing for the Islamic penal code to be implemented in a state it controls, is also competing on Saturday.

Under PAS' hudud laws, adulterers and apostates could face death by stoning, while those found guilty of theft could have their hands amputated.

About 68 per cent of voters in Kuala Kangsar are Malay, 24 per cent are Chinese, and Indians and other ethnicities make up the rest, according to the Bernama news agency.

In Sungai Besar, Malays make up about 67 per cent of voters, while 31 per cent are Chinese and the rest minority groups.

"BN will need to work hard to win, as there are many Chinese who aren't happy about hudud and the fact Umno is trying to get close to PAS," said Mr Yusof Asri, a barber who lives around the Sungai Besar area, gesturing a hand being chopped off. "I'm telling all my friends to vote wisely."