(CNN) Malaysians will go to the polls on Wednesday, May 9, to cast their votes in a parliamentary election that pits incumbent Prime Minister Najib Razak against the combined force of two bitter rivals.

Candidates, who must be nominated on April 28, are expected to include 92-year-old opposition leader Mahathir Mohamad.

Mahatir, who served 22 years as the country's leader before retiring in 2003, has come back determined to topple the party he once led by joining forces with his arch-nemesis, former deputy prime minister Anwar Ibrahim, whom he once jailed for corruption and sodomy.

Mahathir and Anwar have put aside rivalry to focus on defeating frontrunner Najib and his United Malays National Organisation (UMNO) party, which forms the largest constituent in the ruling Barisan Nasional coalition.

Prior to the dissolution of parliament on Friday, Najib's Barisan Nasional coalition held 131 of 222 parliamentary seats.

In the forthcoming elections, voters will cast ballots for Parliamentary seats, as well as on seats in state legislatures.

Malaysian Deputy Prime Minister Ahmad Zahid Hamidi, Prime Minister Najib Razak, and King Abdul Halim Mu'adzam Shah observe the national anthem during the 59th National Day celebrations at Independence Square in Kuala Lumpur on August 31, 2016.

Mahathir's party dissolved

The run-up to the election has been mired in controversy as Najib's government has attempted to further tighten its grip on power. The opposition has accused it of widespread gerrymandering and increasing hand-outs among its ethnic Malay rural powerbase.

Last week Malaysia approved a law against "fake news" that would allow for prison of up to six years for offenders and the slapping of hefty fines, defying critics who say it was aimed at curbing dissent and free speech ahead of the elections.

On Thursday, Malaysian authorities ordered the temporary dissolution of Mahathir's party because of missing paperwork, a move widely said to be an attempt to hamper the opposition.

"The rationale for this is that among less educated and less informed voters this will neutralize some of the Mahathir effect," said Bridget Welsh, a professor of political science at John Cabot University who specializes in Malaysian politics. She added that while it was a "serious blow" to the opposition, it was expected and may backfire.

Speaking to CNN last week, Ibrahim Suffian, a political analyst with the Merdeka Center for opinion research said the action taken may likely further "enrage opposition supporters and energize them."

"While the broader impact is hard to measure ... Mahathir and his allies may make some inroads."

The Registrar of Societies official in charge of political party registration, Surayati Ibrahim, was quoted by media as saying that Mahathir's party could appeal against the ruling or reverse the order "if it provides the required documents within 30 days, failing which it will become permanent."

Mahathir said his Parti Pribumi Bersatu Malaysia (PPBM) will appeal, striking a defiant note by adding that the party "will continue to campaign ... we have the right to use our name and logo till the day RoS deregisters us."

However, Wong Chin Huat, a political scientist at Penang Institute, said Mahathir is unlikely to defy the order and will be able to contest under the banner of another opposition party and will still lead the opposition into the election.

"He won't and he can't because the election commission won't accept nomination of candidates under a deregistered party," he added. "And party membership is not even constitutionally required."

Opinion is divided over whether Mahathir has the clout to oust Barisan Nasional, which has ruled uninterrupted since the country's independence in 1957.

"Structurally Najib has a clear advantage given the unlevel playing field and his control of resources, but the election is fluid and the opposition has been gaining ground in recent months,' said Welsh.

"For now, Najib should win, but the campaign is important in Malaysia and can shift or mobilize the ground. Najib government's heavy-handed tactics in the past few weeks have not helped him."

Malaysia's former Prime Minister and current leader of the opposition, Mahathir Mohamad, addresses his supporters during a rally in Shah Alam, outside Kuala Lumpur on March 27, 2016.

Split opinion

Public dissatisfaction with Najib has grown in recent years, especially after news broke over alleged financial mismanagement of a government-run fund called 1Malaysia Development Berhad, or 1MDB.

Najib has been embroiled in accusations that hundreds of millions of dollars were stolen from the fund, which he formed in 2009 to invest in property, infrastructure and energy projects.

The US Justice Department filed lawsuits in 2016, amended earlier this year, to recover more than $1.7 billion that prosecutors said were laundered through the fund, which is headed by Najib.

US justice officials said that between 2009 and 2015, more than $3.5 billion from 1MDB was misappropriated by high-level officials of the board and associates. Besides the United States, several other countries are investigating the fund.

Najib has been accused of siphoning money from the investment fund after $681 million was transferred into his accounts. He has consistently denied any wrongdoing and said the money was donated by a member of the Saudi royal family.

The 1MDB scandal helped galvanize the opposition and prompted Mahathir to forge an alliance with Anwar, who is back behind bars after being found guilty of sodomy a second time in 2015.

They have agreed that if the opposition wins, Mahathir would be an interim prime minister until Anwar is able to obtain a royal pardon for his sodomy conviction, which disqualifies him from contesting the elections or holding office.

Anwar's wife, Wan Azizah Wan Ismail, is the candidate for the deputy prime minister role.

Rising costs of living and a growing rift among the country's multiracial, multi-religious populace have also dented Najib's popularity.

However, the opposition in Malaysia is weaker now compared with the last election in 2013, when the Barisan Nasional coalition led by Najib limped to the finish line, losing the popular vote and failing to snag a two-thirds majority in parliament.