New South Wales Members of Parliament can continue drinking during late-night sittings, after a parliamentary inquiry ruled drunkenness was covered by existing rules.

The inquiry was launched after allegations that NSW MP Greg Pearce was so drunk in one sitting that he was not capable of voting.

Mr Pearce said exhaustion, stress and illness were merely “compounded” by the effects of “two or three” drinks earlier in the evening.

The former finance minister was later sacked over a conflict of interest in the appointing of executive board members.

President of the Legislative Council Don Harwin said parliamentary inebriation is already covered.

“I take this opportunity to make it absolutely clear that grossly disorderly conduct includes inappropriate behaviour as a result of intoxication by alcohol or any other substance,” he told the chamber.

“Any member who displays such behaviour should therefore expect to be summarily dealt with under the standing orders.”

The report from the inquiry has made suggestions including a midnight cut-off time for parliamentary sittings, so that sessions end before MPs are too tired or drunk.

Thirsty politicians need not look far for a tipple at NSW Parliament House. The public offices feature six licensed areas, including the Strangers' Bar and Members' Bar. Takeaway sales are allowed too, and reports say many MPs keep a well-stocked mini-fridge in their offices.