NSW Opposition Leader Barry O'Farrell says it's unlikely Andrew Fraser will ever return to his frontbench, after the Nationals MP stepped down following his second parliamentary misdemeanour.
Mr Fraser was forced to resign after pushing Nationals MP Katrina Hodgkinson's arm away when she intervened in a heated exchange he was having with Labor MP John Aquilina after a vote in the lower house late on Tuesday night.
"I brushed my colleague's arm aside inappropriately," Mr Fraser told parliament.
"As a result I've apologised to my colleague and I've apologised to the house ... I offer no justification for my actions."
Ms Hodgkinson issued a statement saying she accepted Mr Fraser's apology.
"While Parliament is a place for robust debate, it is a place where I believe the highest standards should be maintained at all times," she said.
"The actions taken on the spur of the moment by the Member for Coffs Harbour last night were unfortunate and inappropriate."
Mr Fraser was suspended from parliament for eight sitting days in October 2005 after he chased then roads minister Joe Tripodi across the chamber and grabbed him by the shirt before being restrained by other MPs and staff.
He was dumped from the opposition frontbench at the time, only to return in January 2006. He went on to be elected deputy Nationals leader following the coalition's 2007 state election loss.
But it has not been a good year for Mr Fraser, who lost his family home in a June fire, and then lost the deputy position in a National Party leadership spill in October.
He was replaced by Murrumbidgee MP Adrian Piccoli.
Tuesday night's incident occurred on the same day Mr O'Farrell warned coalition MPs to be on their best behaviour over the festive season.
A number of government MPs have landed in hot water this year over alleged inappropriate behaviour.
Nationals leader Andrew Stoner confirmed that Mr Fraser had been at the NSW Farmers Federation Christmas drinks but did not know if he was drunk.
Mr O'Farrell said unlike in 2005, he did not see any situation where Mr Fraser would again sit on the coalition frontbench.
"Do I have any plans to bring him back? No," Mr O'Farrell told reporters.
"I can't envisage any circumstances where he will be brought back onto the frontbench."
Deputy Premier Carmel Tebbutt said Mr O'Farrell must completely rule out any chance of that occurring.
"The behaviour of Andrew Fraser in the chamber last night was totally unacceptable," she told reporters.
"That sort of physical, intimidatory behaviour is not acceptable.
"Barry O'Farrell needs to show some leadership and rule out Andrew Fraser ever coming back to the front bench."
Premier Nathan Rees said Mr Fraser's behaviour was a matter for Mr O'Farrell but the incident had occurred at a time when the opposition was voting against his government's new laws for pubs.
"At the same time as Barry O'Farrell was rejecting our legislation aimed at reducing alcohol-related violence, a member of his own side was allegedly engaging in entirely inappropriate activity," Mr Rees told reporters.
The incident caps off another year of NSW MPs behaving badly, with Labor MPs Tony Stewart and Matt Brown both being sacked from the government frontbench for inappropriate behaviour.
Mr Stewart is currently taking legal action in the NSW Supreme Court in an attempt to have his sacking overturned.