Two Australian ministers have resigned in one of the worst political blows to Malcolm Turnbull since he took over as prime minister in September.

One minister quit over his behaviour with a woman in a Hong Kong bar while a second stepped down while he is being investigated by police.

Minister for Cities Jamie Briggs said today he had committed an “error of professional judgment” and did not meet the “high standards required of ministers” when he went to a late night bar during an official visit to Hong Kong last month with one of his staff and a female public servant.

Briggs said the interaction was “informal” and at the conclusion the female public servant went home and he returned to his hotel with his chief of staff.

“However, in the days following the evening the public servant raised a concern about the appropriateness of my behaviour towards her at the venue,” Briggs said in a statement.

“At no point was it my intention to act inappropriately and I’m obliged to note for the record that nothing illegal has been alleged or did in fact occur.”

Briggs, 38, married with three children, said the female public servant took offence “after the event” and he had personally apologised to her.

Briggs was last in the news when he was wheeled through Parliament in a wheelchair after a wild farewell party for the deposed prime minister Tony Abbott. Briggs told reporters he had twisted his ankle jogging, but it later emerged he had been dancing on table tops in the prime minister’s office.

The other minister to step down from the ministry today had been responsible for government integrity, Special Minister of State Mal Brough.

Brough has been under investigation by the Australian Federal Police for several months and his home had been raided amid allegations he misled Parliament and played a role in the illegal copying of diaries of a former parliamentary speaker.

While Briggs had been a supporter of Abbott, Brough was a supporter of current premier Malcolm Turnbull and had been key in the plot to oust Abbott.

Turnbull rewarded Brough with a ministerial post. The appointment was roundly attacked by the opposition Labor party.

- dpa