Malaysians are set to cast ballots in their first election in history with a change of government at stake, as a decades-old leadership battles to hold off an opposition pledging sweeping reform.
Voting gets under way at 8:00am [0000 GMT] on Sunday with tensions high after a bitter campaign in the multi-ethnic country marked by charges of election fraud, divisive racial rhetoric and widespread violence.
Malaysians have awaited the vote since 2008 polls saw a newly united opposition make unprecedented gains against the
once-invincible coalition that has had a lock on power since independence in 1957.
The coalition dominated by the United Malays National Organisation (UMNO) and led by premier Najib Razak has been expected to edge the Pakatan Rakyat (People's Pact) alliance captained by former UMNO member, Anwar Ibrahim.
But recent opinion polls have indicated the race was too close to predict.
Pakatan has capitalised on anger over corruption, authoritarianism and controversial policies that favour majority ethnic Malays, while wooing minorities and a younger generation exposed to alternative views found online.
Pakatan pledges sweeping reform, including an end to cronyism and corruption that it says sustains a powerful elite.
'We will win'
The opposition has set the stage for a possibly disputed result with numerous accusations of Barisan electoral fraud.
These include an alleged scheme to fly tens of thousands of people of "dubious" and possibly foreign origin to key constituencies to sway results.
The government claims the flights were part of a voter-turnout drive.
Indelible ink applied to voters' fingers to prevent multiple voting - touted by Najib as a safeguard against fraud - also was found to wash off.
"Unless there's a major massive fraud tomorrow... we will win," Anwar told the AFP news agency on Saturday.
Anwar, a former deputy premier ousted in a 1998 power struggle and jailed six years on sex charges widely viewed as trumped up, has drawn festival crowds in the tens of thousands on the stump.
But it remains to be seen whether Malaysians will vote out the only government they have ever known, and Najib has played on fears for stability while pledging continued solid economic growth.
His ethnic Malay-dominated regime retains powerful advantages, including control of traditional media and an electoral landscape critics say is biased.
Najib also has exploited racial and religious insecurities by claiming a conservative Islamic party within Pakatan would implement sharia law.
The occasionally fractious opposition, which also includes Anwar's multi-racial party and a secular one dominated by minority ethnic Chinese, condemns such rhetoric as dangerous racial fear-mongering.
Campaigning has been marred by hundreds of reports of violence, intimidation, arson and two small explosions, although no deaths have been reported.
Polling stations close at 5:00pm [0900 GMT] with results expected to begin rolling out within hours.