Ms Siddiq, who is Ms Hasina’s niece, resigned from her post as an anti-corruption minister in Prime Minister Sir Keir Starmer’s government in January after reports that she lived in London properties linked to her aunt and was named in an anti-corruption investigation in Bangladesh.
She is being tried together with her mother, Sheikh Rehana, brother, Radwan Mujib, and sister, Azmina.
Ms Siddiq has been charged with facilitating their receipt of state land in a township project near the capital, Dhaka.
The four were indicted earlier and asked to appear in court, but the prosecution said they absconded and would be tried in absentia.
The trial at the Dhaka Special Judge Court-4 formally began on Wednesday, hearing evidence from officials from the country’s Anti-Corruption Commission.
The court had heard from two officials and a third was expected to testify later in the day, Muhammad Tariqul Islam, a public prosecutor, said.
Ms Siddiq’s lawyers had previously called the charges baseless and politically motivated.
Separately, the anti-corruption investigation has also alleged that Ms Siddiq’s family was involved in brokering a 2013 deal with Russia for a nuclear power plant in Bangladesh in which large sums of money were said to have been embezzled.
The Labour MP represents the north London district of Hampstead and Highgate and served as economic secretary to the Treasury — the minister responsible for tackling financial corruption.
Ms Hasina was ousted after a 15-year rule in a student-led mass uprising in August last year. She fled to India and has been in exile ever since.
Nobel Peace Prize laureate Muhammad Yunus took over as interim leader and vowed to try the former prime minister.
Hundreds of protesters were killed during the uprising and Ms Hasina now faces charges, including crimes against humanity.
