PETALING JAYA • Malaysian Prime Minister Mahathir Mohamad said yesterday that a serious post-mortem needs to be done to identify why the ruling Pakatan Harapan (PH) alliance was defeated in the Tanjung Piai by-election over the weekend.

"A detailed, serious and honest post-mortem must be made at all levels of the parties to find out what was the real reason for the by-election defeat," Tun Dr Mahathir said in a statement following the alliance's loss last Saturday in the constituency in Johor state.

The PH chairman said that he expected the opposition to win by a 2,000-vote majority, adding that the 15,086-vote defeat was much worse than he anticipated.

"I take note of the results of the recent by-election. I accept the results made by the people of Tanjung Piai," said Dr Mahathir, who is the chairman of Parti Pribumi Bersatu Malaysia, a member of the PH alliance.

This is the first time he has spoken publicly about the worst by-election defeat for PH since taking over the federal government last year.

The Tanjung Piai by-election saw a candidate from the opposition Barisan Nasional (BN) coalition, Datuk Seri Wee Jeck Seng, win with an overwhelming 15,086-vote majority. Dr Wee, a former two-term Tanjung Piai MP from the BN's Malaysian Chinese Association (MCA) party, garnered a total of 25,466 votes against the PH candidate from Dr Mahathir's Bersatu party, Mr Karmaine Sardini, who obtained 10,380 votes.

The other four candidates, from smaller opposition parties and independents, together received fewer than 3,000 votes.

The Tanjung Piai by-election - triggered by the death of the incumbent PH lawmaker-saw the two biggest opposition parties, Umno and Parti Islam SeMalaysia, campaigning together for the first time since signing a unity charter in September.

Along with the MCA, they set aside their ideological differences to gain victory in the ethnically diverse constituency.

PH unexpectedly swept to power in the May 2018 election with promises to crack down on corruption, move away from race-based policies and bring down the price of goods and services.

But slower-than-expected reforms, living-cost woes and bickering among leaders have led to disillusionment among some voters, and the alliance has been defeated in four of nine by-elections since then.

PH's top leaders, including Dr Mahathir and his designated successor Anwar Ibrahim, had made trips to Tanjung Piai to convince voters to keep them in power.

"The majority that the opposition garnered is a shock and it's a clear message to all PH leaders," Datuk Seri Anwar said in a Facebook post last Saturday after the outcome.

THE STAR/ASIA NEWS NETWORK, BLOOMBERG