The opposition alliance Pakatan Rakyat (People's Pact) led by Anwar Ibrahim, a former deputy prime minister who was booted out of the BN coalition 15 years ago, has unveiled a 100-day roadmap including waiving all higher education loans, and abolishing highway tolls if voted to power.
A total of 13.2 million are eligible to vote in the multi-ethnic Muslim majority country.
The country's 29 million people includes 60 per cent Malays who are all Muslims, 25 per cent ethnic Chinese who are mostly Christians and Buddhists and eight per cent ethnic Indians who are mostly Hindus.
The last polls had seen a huge swathe of ethnic Indians supporting the opposition alliance.
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An independent survey showed the ruling coalition was running neck and neck with the opposition alliance.
The Barisan holds 135 seats in the 222-member Parliament, while Anwar's group has 75 seats.
Najib has offered a stable government with all races looked after.
By late this evening it will be known if Malaysians will vote out the only government they have known.
Campaigning has been dotted with many reports of violence, arson and two small explosions. Polling stations will close at 5:00 pm (0900 GMT).
Eighteen international observers from Asia including representatives from ASEAN Secretariat have been invited by the government.
Also, for the first time in the country's history indelible blue ink is being used on voters.
Anwar's alliance shot into political limelight in the 2008 general elections when it won more than a third of seats in parliament and gained control of several states, taking the Barisan totally by surprise.