Malaysia's former first lady, who allegedly bankrolled a luxurious lifestyle with kickbacks and stolen public money, went on trial Wednesday for corruption for the first time since her husband lost power.

Rosmah Mansor, notorious for making overseas shopping trips and owning vast collections of handbags and jewellery, became a lightning rod for public anger as the government of prime minister Najib Razak was engulfed by corruption allegations.

Her husband's long-ruling coalition suffered a shock election defeat in 2018 in large part due to claims he and his officials plundered billions of dollars from sovereign wealth fund 1MDB.

Both Najib and his wife have since been hit with multiple charges over the looting of the investment vehicle, but Rosmah's first trial centres on allegations she received bribes linked to a government project.

Prosecutors allege she pocketed 6.5 million ringgit ($1.6 million) for helping a company secure the project to provide solar power generators to schools on the Malaysian part of Borneo island.

The 68-year-old is also accused of soliciting a further 187.5 million ringgit. Rosmah faces three counts of corruption for the offences, which allegedly took place in 2016 and 2017.

Rosmah, known for her imperious manner and enormous mane of hair, denied all the charges as proceedings began at the Kuala Lumpur High Court.

The former prime minister's wife "occupied no official position. However, she wielded considerable influence by her own overbearing nature", said prosecutor Gopal Sri Ram in his opening statement.

"She placed herself in a position where she was able to influence decisions in the public sector."

The trial was supposed to start Monday but was delayed after Rosmah was admitted to hospital complaining of neck pain. On Wednesday she arrived in a car followed by an ambulance, and limped into the courtroom.

Najib, who is on trial at the High Court over the looting of 1MDB, made an appearance in the courtroom as the trial got underway.

The former leader and his wife's lavish lifestyles came to symbolise the perceived rot in Malaysia's ruling elite.

Following the 2018 election, police discovered valuables -- including cash, jewellery and luxury handbags -- worth up to $273 million in properties linked to the couple.