Malaysian prosecutors are expected to add new charges to Rosmah Mansor, wife of ex-Prime Minister Najib Razak, while another former senior minister was arrested for prosecution on Wednesday.

Rosmah and her former special officer will face charges in connection with a solar power project for schools, Malaysian Anti-Corruption Agency (MACC) said in a statement.

Rosmah and the officer had been summoned to complete the final process of the investigation and prosecution.

It had been previously alleged that the solar panel project, involving more than 300 schools, was awarded to a company without an open tender with the endorsement by Najib.

Rosmah already faces 17 money laundering and tax-evasion offences involving 1.6 million U.S. dollars.

Meanwhile, Tengku Adnan Tengku Mansor, the federal territories minister in Najib's government who had served as secretary-general of the United Malays National Organization (UMNO), was arrested by MACC.

"MACC has been given consent to prosecute former Federal Territories Minister, Tengku Adnan Tengku Mansor, related to the sale of the Kuala Lumpur City Hall land," said the anti-corruption body.

It added that Tengku Adnan is expected to be charged jointly with a businessman at a Kuala Lumpur court.

UNMO has led a coalition to govern Malaysia for 60 years until suffering defeat in the general election in May.

Najib himself faces 38 corruption charges involving billions of dollars in public funds connected to the 1 Malaysia Development Berhad (1MDB) scandal.