Tide turns against PM who has been mired in scandal as support surges for country’s former leader Dr Mahathir Mohamad

The Malaysian prime minister, Najib Razak, is facing a fight for his political survival when the country goes to the polls this week, after his strong lead over rival Dr Mahathir Mohamad narrowed sharply.

Najib, who has been in power since 2009, was initially thought to be guaranteed an easy win in Wednesday’s elections. But in the past few weeks the tide has turned against him, even in the rural Malay heartlands that have long been strongholds for the ruling coalition, Barisan Nasional (BN).

'This election is personal': Mahathir Mohamad, 92, vows to stop 'corrupt' protege Read more

Many are now predicting that the government will once again lose the popular vote, though thanks to recent gerrymandering and the redrawing of electoral boundaries it will still be able to hold on to power.

Figures within Umno, Najib’s party in the ruling coalition, say that if Najib wins fewer than 130 seats out of a total of 222 (BN currently holds 133), then he is likely to face a post-election leadership challenge.

Most of the election narrative has been controlled by the opposition, led by former prime minister Mahathir, who led the country between 1981 and 2003, and at 92 years old has returned to topple Najib, his former protege. Mahathir was once head of Umno himself but has switched sides in this election to run against Najib.

Najib has also faced growing criticism from within his own party. Last week Umno sacked two senior leaders and suspended another – all long-time loyalists of Mahathir – for speaking against Najib and attending opposition events.

Much of the criticism of Najib has been focused on his role in the huge 1MDB scandal, where $2.6bn from a government fund he was overseeing was embezzled and spent around the worldand $681m of it was alleged to have ended up in his personal bank account.

Q&A What is the 1MDB scandal? Show Hide The 1Malaysia Development Berhad fund was set up in 2009 by Najib Razak to promote economic development in Malaysia. Its advisory board was chaired by Najib and as finance minister he held veto power over its activities. Between 2009 and 2014, top executives and associates of Najib looted $4.5bn from the fund, laundering it through the US, Singapore, Switzerland and other countries, according to a US justice department civil case seeking to recover part of that money. The US says the money it is seeking to recover was gambled in Las Vegas, used to buy hotels, apartments, a luxury yacht, a jet, diamond jewellery and art works and to finance Hollywood films including the Wolf of Wall Street and Dumb and Dumber To. About $700m landed in Najib's bank account, though he denies any wrongdoing. 1MDB now staggers under enormous debt, has sold assets to Chinese interests and is set to be wound up. Outraged by the scandal, Malaysia's former leader Mahathir Mohammad came out of political retirement and the opposition has united behind him in the upcoming national elections. The government recently passed a "fake news" law that could be used to further stifle reporting on the case within Malaysia. Agence-France Presse Photograph: Olivia Harris/X90169

“I think there’s definitely momentum for change happening across the country,” said Bridget Welsh, a Malaysia expert from John Cabot University. “Najib walked into this election very strong and it was his election to lose. But so far in the campaign he has been losing the narrative and as a result there has been a lot of movement away from him.”

While opposition rallies have been packed out, and the “Mahathir factor” has drawn a lot of media attention towards the opposition, the election will be decided by a large silent majority, many of whom live in remote rural areas of Malaysia and traditionally have voted for BN.

Among rural farmers and ethnic Malay in states such as Sabah and Sarawak – which account for 60% of Malaysia’s land mass – Najib demands huge loyalty for the generous subsidies given out, and issues such as the 1MDB corruption scandal do not factor in their voting choices.

For Najib to lose the election it would require a huge swing away from him in these areas, which is still unlikely.

In a statement released on Monday, Najib took a final dig at the opposition “whose only reason for coming together is to selfishly gain power for themselves”.

“Do not be fooled either by the tears and the ridiculous allegations of sabotage or even assassination,” Najib said of Mahathir. “A former dictator, as he has called himself, does not change. He has apologised sincerely for nothing. The truth is he trying to use his former allies, just as they are trying to use him. Their hypocrisy is breathtaking.”

There is also concern that with the election result likely to be tight, unfair and nefarious tactics such as vote-buying might be more rife than usual. The Human Rights Commission of Malaysia has had its application to monitor the election denied.

Instead the election will be overseen by observers from a selection of countries with questionable democratic credentials, including Indonesia, Thailand, the Maldives, Timor-Leste, Azerbaijan, Cambodia and Kyrgyzstan. Only Timor-Leste is considered a free democracy by Freedom House, while Thailand is run by an unelected military government, and Kyrgyzstan and Azerbaijan are classified as authoritarian regimes.

According to Welsh, the election drama and cult of personality around Najib are likely to spin out long after polling day. “The narrative is all about Najib and he has taken a risk by making it all about him, so that could come with high rewards or high losses,” she said. “Whatever happens, we are definitely heading towards a scenario of change.”