The Hope Alliance, led by former Prime Minister Mahathir Mohamad, also promised to clip the powers of the prime minister, revive fuel subsidies and a slew of economic reforms as part of its manifesto for polls due by August but widely expected in the second quarter.
In announcing the coalition's manifesto late Thursday, Mahathir said the opposition has been labelled "government-in-waiting" as he rallied supporters to unite to oust the coalition that has ruled since independence.
"This book contains so many promises that we will fulfil once we get to Putrajaya," said Mahathir, who led Malaysia for 22 years before he stepped down in 2003. "Some are now calling us a government in waiting ... but that won't happen if we don't work for it."
At 92, Mahathir will be the world's oldest prime minister if the opposition wins but he promised to hand over the reins once his former deputy Anwar Ibrahim is released from prison in June and able to take over. Analysts say the opposition faces an uphill battle due to party infighting, unfavorable electoral boundary changes and strong support for the government from rural ethnic Malays.
Support for Najib's ruling National Front coalition has dwindled in the last two elections as he struggled with an epic corruption scandal that involved hundreds of millions of dollars believed linked to the 1MDB state fund passing through his bank accounts. In 2013, the coalition lost the national popular vote for the first time to the opposition.
The U.S. and several other countries are investigating allegations of cross-border embezzlement and money laundering at 1MDB, which was set up and previously led by Najib to promote economic development but which accumulated billions in debt. Malaysia's attorney-general cleared Najib of any wrongdoing in 2016.
The opposition said it will set up royal bodies to reinvestigate the 1MDB scandal and probe other scandal-plagued government agencies such as the Federal Land Development Authority.
The manifesto pledged to limit the prime minister's tenure to two terms, bar the premier from holding multiple posts and halve the annual budget for the premier's office. Najib currently holds the powerful finance minister post.
If it wins, it will abolish the 6 percent goods and services tax introduced in 2015 and blamed for a spike in the cost of living. It will also revive fuel subsidies for targeted groups, raise minimum wages and study plans to give autonomy to the east Malaysian states of Sabah and Sarawak - the country's two poorest states which are substantial vote bank that helped Najib stay in power.
Government leaders poured scorn on the opposition's manifesto. Minister in the Prime Minister's Department Abdul Rahman Dahlan tweeted that the manifesto was "pure rhetorics. There are no new promises that are fresh and realistic and could benefit the people."
James Chin, director of the Asia Institute at Australia's University of Tasmania, said pledges to limit the premier's power will bolster democracy in Malaysia. He said the manifesto was a combination of populist measures and serious reforms.
"The issue going forward is whether voters believe if the opposition alliance can deliver on its promises if it wins power," Chin said.
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