Dhaka, Aug 4 - Bangladesh opposition leader Khaleda Zia's younger son Arafat Rahman Koko has challenged his trial for alleged corruption in two deals, one with German telecom major Siemens and the other with a Chinese firm.

From his sick bed in Bangkok, Koko filed a writ petition in the high court challenging the legality of the proceedings of the case against him.

The Anti-Corruption Commission March 17 filed the case against Koko, charging him with illegally transferring 2,884,603.15 Singaporean dollars and $932,672.81 to three accounts in Singapore banks.

His lawyer argued that the alleged offences took place between 2001 and 2006, when Khaleda Zia was in power, but the case was filed against Koko under the Money Laundering Act 2009 that was enacted this year.