Monday is the first day of hearing for Rosmah, 69, who is accused of three counts of graft amounting to hundreds of millions of ringgit involving a solar hybrid project in Sarawak, reports The Star newspaper.
She allegedly solicited for herself a 187.5 million ringgit ($45 million) bribe from Jepak Holdings, through her former aide Datuk Rizal Mansor.
The money was a reward for helping Jepak Holdings obtain a project, through direct negotiations with the Education Ministry, for installing solar hybrid systems and the maintenance and operation of diesel generators for 369 rural schools in Sarawak.
The project was valued at 1.25 billion ringgit.
For the second charge, she was accused of receiving 1.5 million ringgit as a reward for assisting Jepak Holdings obtain the same project.
Rosmah was charged again for allegedly receiving a bribe of 5 million ringgit for the same purpose, according to The Star newspaper report.
Meanwhile, Najib's trial for the corruption charges related to the state investment fund 1Malaysia Development Berhad (1MDB) has also resumed.
He is still on the stand for his defence.
The 67-year-old is facing seven charges three charges of criminal breach of trust, one count of abusing his position and three counts of money laundering related to SRC International funds, a former subsidiary of 1MDB.
Najib has pleaded not guilty to all the charges.
( With inputs from IANS )