Malaysian Prime Minister Najib Razak dissolved parliament Wednesday in preparation for a general election seen as the toughest challenge yet for the ruling coalition after 56 years in power.
The vote is tipped to be the closest ever, driven by concerns over corruption, the rising cost of living and high crime under the Barisan Nasional coalition, which has ruled Malaysia since independence in 1957.
The resurgent opposition, led by charismatic former deputy premier Anwar Ibrahim, has gained traction by pledging to tackle authoritarianism and graft.
But with widespread allegations of vote-rigging, there are fears that the election, which must be staged in the next 60 days but is likely to be held this month, will not be free and fair.
In his televised announcement of the dissolution of parliament, Najib, the son of a former prime minister, urged political parties to observe the rule of law and promised a smooth transition of power if the opposition wins.
"If there is change in power, it will and must happen peacefully. This is our commitment," he said.
Najib is facing his first test at the ballot box since taking over in 2009, after the coalition lost its traditional two-thirds parliamentary majority in a shock election result.
In Wednesday's broadcast, he urged the electorate not to "gamble" away their vote by opting for an untested opposition, the three-party Pakatan Rakyat (People's Pact).
But Anwar said Najib's leadership was showing "signs of desperation".
"For Pakatan Rakyat it is the best possible chance to offer a viable alternative for democracy and a more responsible government. I think the chances of winning are very good," he told AFP.
He later told reporters that he welcomed Najib's promise of a peaceful transition if Pakatan won and hoped the country's Election Commission would conduct "its duties fairly".
Anwar was barred from contesting in the last elections after he was convicted of sodomy and corruption in the late 1990s -- widely seen as politically motivated due to a fallout with then premier and his boss Mahathir Mohamad.
He was acquitted of new sodomy allegations in 2012 after a two-year trial during which he accused the government of again trying to end his career.
Activists and the opposition have made loud calls for free and fair elections, staging several mass rallies demanding such changes as a clean-up of the electoral roll, which they say is marred with irregularities.
In response, Najib's government has taken steps including the introduction of indelible ink to prevent multiple-voting and allowing Malaysians abroad to vote by post.
But the opposition says these moves fall short of creating a level playing field.
Independent pollster Ibrahim Suffian with Merdeka Center said he expects elections to be held on the week of April 27 as campaign periods between nomination and polling days have traditionally been less than two weeks.
"The campaign period will be short," he said. "The opposition right now looks very energetic... It makes for a very competitive election."
Najib has worked hard to rebrand his United Malays National Organisation (UMNO), which dominates the 13-member Barisan coalition, by launching a series of reforms aimed at boosting the economy and granting greater civil liberties.
The opposition currently holds 75 of 222 parliamentary seats and controls four of the country's 13 states.
UMNO's uninterrupted rule has seen decades of economic expansion and there was better-than-expected 5.6 percent growth last year, spurred by consumer spending supported by pre-election direct cash handouts and other incentives.
But criticism of the government's authoritarian rule is growing and the opposition is promising a new era of political liberalisation and an end to entrenched corruption.