Alan Tudge, who is now acting immigration minister, has publicly apologised for the hurt his 2017 affair caused his family and former staffer Rachelle Miller.

However, Attorney-General Christian Porter has denied accusations of any wrongdoing, having been told by former prime minister Malcolm Turnbull reports of him drinking and being seen “in the company of young women” at a Canberra bar in late 2017 exposed him to the risk of compromise.

Turnbull instituted a so-called “bonk ban” – extending the ministerial code of conduct – when media reports exposed former deputy prime minister Barnaby Joyce as having an affair with a staffer who was pregnant.

Morrison as prime minister kept the ban in place, arguing while it was “regrettable” to have to put such things in writing it was the right thing to do in terms of providing a professional workplace in Parliament House.

This morning, Morrison faced questions about the allegations against Porter and Tudge and repeatedly said they had been dealt with by Turnbull. He dismissed calls for an investigation.

Morrison said he had spoke to the ministers concerned and was confident there had been no similar allegations under his prime ministership.

“My ministers are in no doubt about what my expectations are of them,” Morrison said.

“Absolutely no doubt.”

Morrison challenged any suggestion the allegations were confined to the Liberal Party – “you reckon?” – and also sought to suggest journalists working in Canberra faced similar ethical risks as politicians.

“Our government responded by putting in standards that don’t exist in many of your newsrooms,” Morrison said.

Turnbull met with Porter just before making him attorney-general, telling him the reported behaviour was “unacceptable conduct for a cabinet minister” – especially one who was soon to take on a major national security portfolio.

Turnbull’s remarks made on ABC’s Four Corners program on Monday night also aired background on Porter related to his attitude towards women when he was at university.

In a statement, Porter apologised for some material he wrote in a law school magazine 24 years ago, but denied other reflections on his character and said he was considering legal action.

“Four Corners’ depiction of interactions in the bar are categorically rejected,” he said in a statement.

Turnbull later told ABC’s Q&A program after Four Corners aired: “If I’d known at the time what was broadcast … I would have made further inquiries before I made him attorney-general.”

Miller told Four Corners that her consensual affair with Tudge cost her “a lot of self-confidence” and she felt powerless in the situation.

Victorian Premier Daniel Andrews applauded the women who spoke up in the program.

“It is not easy to speak out and call out appalling behaviour.”

However, Joyce argued a politician’s private life should only become public when there were issues around age, agency or consent.

“If it’s a consensual relationship between two adults, then if you’ve got a problem with that, that’s a role for the police or a priest, but not another politician to be the arbiter of how two people feel about each other,” he said.

Labor MP Andrew Leigh said all political parties needed to accept there was “serious work to be done” around behaviour standards.

“Women have the right to feel safe and respected in any workplace, and the federal parliament needs to be no different.”

-AAP