Voting is underway in the by-election in Rompin in the eastern state of Pahang where Umno is expected to comfortably retain the parliamentary seat it won with a big margin in the last general election.
The Rompin seat was left vacant by the late Tan Sri Jamaluddin Jarjis, an Umno lawmaker and key ally of Prime Minister Najib Razak, who was killed in a helicoper crash last month. He won the seat two years ago with a 15,114-vote majority, garnering about two-thirds of the 86 per cent turnout.
The Election Commission expects a slightly lower turnout of 80 per cent in Tuesday's by-election. A significantly lower turnout in Rompin would be as much a sign of protest as a drop in Barisan Nasional's winning margin. More than half of the voters are Umno's entrenched votebank of Felda settlers - rural Malays given homes and land to farm cash crops.
The by-election is taking place amid widespread unpopularity over the Goods and Services Tax (GST) implemented on April 1.
BN has been trying to disassociate the local vote from the new levy. Domestic Trade, Cooperatives and Consumerism Minister Hasan Malek was chastised as "stupid" by Umno candidate Hasan Arifin for saying that the Rompin by-election result would be an indicator of public acceptance towards the GST. Deputy Prime Minister Muhyiddin Yassin also said the poll should not be linked to the tax which is crucial for BN's plans to cut growing national debt.
Analysts say the current GST rate of 6 per cent will cause inflation to rise to between 4 to 5 per cent this year, likely fuelling further public anger over rising cost of living.
Parti Islam seMalaysia (PAS) candidate Nazri Ahmad has also had his share of problems, as the party's coalition partners - Democratic Action Party (DAP) and Parti Keadilan Rakyat (PKR) - have been missing from the two-week campaign, coming off the back of fierce protests against the Islamic party's push for hudud, the Islamic penal code that proscribe stoning and amputation, among other forms of punishment.
Rompin has 53,294 registered voters, 88 per cent of whom are Malay Muslims, and their choice could also be seen as indicative of whether they support PAS' hudud law that has been presented to Parliament. The house sits again on May 18.
The by-election is the ninth to be called since the 13th general election in May 2013, and will be followed quickly by the Permatang Pauh vote on May 7 that is also being contested by Umno.