With nearly 15 million registered voters, polls opened at 00:00 GMT on Wednesday across the country and closed at 09:00 GMT.
Malaysia’s 14th general election pits incumbent Prime Minister Najib Razak, who is seeking a third term, against his one-time mentor and former Prime Minister Mahathir Mohamad.
Najib, who has been in power since 2009, cast his ballot in the city of Pekan.
“It’s been a calm election in terms of the physical aspect of the election,” he told reporters.
“It’s not been that tense, but it has been quite vicious in the content of the personal attacks which doesn’t reflect a mature democracy,” he added.
“But the most important thing is for the people to decide on the destiny of this nation, and it must be based on facts, it must be based on policy, it must be based on who can execute the best plan for the nation and for the people.”
By 05:00 GMT, voter turnout was at 55 percent – lower than the last election in 2013, according to statistics released by the Election Commission.
Al Jazeera’s Florence Looi, reporting from the capital, Kuala Lumpur, said it was the first time voting was held mid-week.
“The government declared it as a public holiday, but it is still going to make it quite difficult for some people who are working, perhaps in the bigger cities, but are still registered to vote in their hometowns and small areas, who have to travel back to vote,” Looi said.
Najib’s ruling right-wing party, Barisan Nasional, has been in power since the country gained independence in 1957.
But allegations of his links to a corruption scandal involving a state-owned investment fund has cast a shadow over his election campaign. Najib has denied any wrongdoing in the case.
Meanwhile, his main challenger, Mahathir quit his old party and gave the opposition a boost when he forged an alliance with them.
The 92-year-old’s return to politics, as chairman of Pakatan Harapan, or Alliance of Hope, gave a new lease of life to the opposition alliance, which had been floundering since its leader Anwar Ibrahim was jailed for sodomy on what his supporters said were politically motivated charges.
“You’ve got two political heavyweights leading the battle,” said Al Jazeera’s Looi.
According to polls on Tuesday, Najib’s ruling Barisan Nasional party could take up to 100 seats out of the 222 up for grabs in the parliament, falling short of a clear majority win.
Al Jazeera’s Looi said: “37 seats are too close to call”.
Among the key election issues has been the rising cost of living in the country, with many voters placing blame on the goods and services tax that was imposed three years ago.
“I hope personally and maybe people share my thoughts, we hope for some kind of change that will bring prosperity to our country,” Zulkifli Bin Mat Saad, a voter, told Al Jazeera.
“So, whoever it is [that wins] please stay true to whatever manifesto or promises, and hold on to those promises and principles.”
Another voter, Muhamad Nursuhairi, said: “I feel so lucky and happy, that I could vote today. And that I could exercise my responsibility as a Malaysian citizen.”