The federal Nationals deputy leader Perin Davey has admitted to drinking before speaking during a parliamentary hearing but says she was not drunk.

Senator Davey stumbled while speaking at the hearing, which was held days after colleague Barnaby Joyce was filmed lying on a Canberra footpath on 7 February.

Prime Minister Anthony Albanese said all MPs must behave responsibly.

"I think that politicians have a responsibility to think about the great honour that we have of representing our electorates," he told a press conference in Nowra.

According to the Sky News, Senator Davey said she went to Nationals staff drinks where she had two glasses of wine before attending an estimates hearing.

"I wouldn't say I was under the weather. I stumbled over my words. If you want to pick on people who stumble over their words, there are plenty of Labor MPs [who do so]," she said.

The incident occurred just four days after footage emerged of Mr Joyce lying on Lonsdale St in Braddon late at night, speaking to his wife Vikki Campion on the phone and swearing after having fallen off a bench.

The Nationals, Liberals and Country Liberal Party have been strident in criticism of Labor's handling of alcohol restrictions in the Northern Territory and elsewhere, and have on occasion floated linking welfare payments to drug and alcohol testing.

Independent MP Zali Steggall has advocated random alcohol and breath testing for members of parliament.

Australian Greens housing spokesman Max Chandler-Mather told the ABC he did not think drug and alcohol testing in any workplace was necessarily a good idea, but added "certainly I think people are justifiably upset at the standard politicians hold themselves to".