Dewan Rakyat deputy speaker Nga Kor Ming has been urged to refrain from partisan behaviour outside of Parliament.

NGO Engage said the Perak DAP chief should maintain the commendable neutral stance he shows in the Dewan Rakyat until parliament is dissolved.

"We are disturbed by his highly partisan behaviour outside of the Dewan Rakyat, especially in the Balakong by-election.

"He has engaged with MCA in highly partisan language, mocking MCA's logo by saying it looks like a 'durian' and accusing MCA of trying to cheat voters by using their own logo to contest the Balakong by-election.

"Such verbal broadsides are in sharp contrast with the neutral and measured manner in his parliamentary role.

"It is unreasonable to expect parliamentarians and the public to treat Nga the parliamentary deputy speaker, and Nga the DAP parliamentarian, as two different persons with different temperaments and believe the former can be impartial," said Engage chairperson Thomas Fann in a statement.

Fann said the public's expectation for Nga to remain neutral in and outside of parliament also extends to fellow deputy speaker Rashid Hasnon, who is PKR's Batu Pahat MP.

Nga had significantly toned down his firebrand attitude after he was elected Dewan Rakyat deputy speaker.

His conduct in the august House has won praise, including from Umno mouthpiece Utusan Malaysia.