The lord mayor of Melbourne has stood down for a month amid allegations of sexual harassment.

Robert Doyle announced on Sunday he was taking leave while an investigation into claims against him takes place.

“My decision to take leave must not be interpreted as any concession or admission,” Doyle said in a statement.

Doyle said he had been officially informed of an allegation against him on Sunday morning.

“I welcome the investigation and will cooperate fully to clear my name,” he said. “I am shocked. I have not been officially informed of the specifics but find the allegations detailed to me by media outlets thoroughly abhorrent, not only as lord mayor but as a father of young women, a husband, a brother and as the head of an office made up entirely of women.”

Doyle said he was “frustrated” that he had not been given specifics of the allegations and said the release of details to the media was a “strategic” act that was damaging to his reputation and a “denial of natural justice”.

The City of Melbourne chief executive, Ben Rimmer, said he was made aware of the allegations on Friday night and had ordered an external investigation to be headed by Ian Freckleton QC.

“On Friday evening I was made aware of serious allegations – including sexual harassment, indecent assault and misconduct – against the lord mayor, Robert Doyle AC,” Rimmer said in a statement. “I have today informed the lord mayor that these allegations have been made.”

Doyle’s announcement comes after it emerged City of Melbourne councillor Tessa Sullivan left her job on Friday.

Sullivan had resigned “after herself and other women had experienced repeated sexual harassment which had made their workplace intolerable”, Melbourne council told the Age on behalf of Sullivan.