KUALA LUMPUR (AFP) - A top Malaysian opposition MP was sentenced Wednesday (Sept 28) to three months in jail after being found guilty of sedition over statements urging protests against Prime Minister Najib Razak's government, lawyers said.

Mr Najib has come under fire for using repressive laws against critics and stifling scrutiny of a massive corruption scandal involving state investment fund 1MDB that he is allegedly embroiled in.

Chua Tian Chang, better known as Tian Chua, was found guilty of sedition for inciting Malaysians to take to the streets to rally against corruption in 2013.

Chua, who is the vice-president of the opposition Parti Keadilan Rakyat, said the court decision reflected the "growing intolerance" of Mr Najib's regime.

"There is growing intolerance against critics. The government aims to stop people from voicing out," Chua, who is freed on bail, said.

The sessions court also hit the vocal MP with a fine of RM10,000 (S$3,291) in a decision slammed by rights groups.

Chua's lawyer N. Surendran said an appeal will be filed.

Last year, Mr Najib purged his government of critics and shut down domestic investigations while the number of activists facing court action and police probes has shot up.

The 63-year-old premier is clinging to power despite increasingly damaging allegations that he took part in the looting of billions in state funds. Mr Najib and 1MDB have repeatedly denied wrongdoing in the scandal.

Amnesty International Malaysia described Wednesday's court ruling as a "setback" for freedom of expression.

"The ability of individuals to criticise the state... must not be criminalised," Ms Shamini Darshni, Amnesty International Malaysia executive director, said in a statement.