The opposition leads the coalition 52 to 48 on a two-party preferred basis in Monday's poll published in The Australian.

The government is under immense pressure following former Liberal staffer Brittany Higgins alleging she was raped by a colleague in a minister's office.

Defence Minister Linda Reynolds is on medical leave after scrutiny over her handling of the complaint.

Attorney-General Christian Porter is also taking time off after emphatically denying separate historical rape allegations against him.

Protesters have descended on Parliament House to demand more action on violence and harassment against women.

Deputy Prime Minister Michael McCormack described recent weeks as sad and complex but said a number of factors were behind the Newspoll.

"If you don't like one poll there'll be another next week, next month," he told the Seven Network.

The Nationals leader attempted to deflect the slide in support by pointing to a poll showing NSW Labor was struggling against the state coalition government.

Government Senate Leader Simon Birmingham wouldn't be drawn on whether the issues surrounding the attorney-general and Ms Higgins had damaged the coalition's standing with voters.

"The government won't be spending much time worrying about polls," he told ABC radio.

Senator Birmingham said the government would remain focused on economic security and the coronavirus vaccine rollout, as well as the protesters' concerns.

Nationals MP Barnaby Joyce said the government should be honest about what was behind the numbers.

"Yes the Christian Porter, the Brittany Higgins issue has certainly affected our vote," he told Seven.

"It's something we have to address. It's something we have to give confidence to the Australian people to deal with."

But he believes if allegations against Labor staffers had surfaced at the same time then both major parties would have been "hit for six".

Labor MP Joel Fitzgibbon said Newspoll and the WA government's obliteration of the Liberals at the weekend showed the federal opposition should win the next election.

"The Labor brand is alive and well," he told Seven.

Mr Fitzgibbon urged the ALP to focus on families' safety and economic security ahead of the next poll.

"If we can stick to those subjects and prosecute them well we will and should win the next election."

Newspoll shows Labor and the coalition's primary votes are locked at 39 per cent each, with the Greens sitting on 10 per cent and One Nation on three per cent.

Scott Morrison remains a clear leader in the better prime minister stakes, leading Anthony Albanese 56 to 30 per cent.

The Newspoll is based on an online survey of 1521 respondents between Wednesday and Friday.

Australian Associated Press