The archbishop of Brisbane, Mark Coleridge, is under investigation for his treatment of a woman who offered information on child abuse within the Catholic church more than a decade ago.

Last week Coleridge attended a four-day meeting at the Vatican on child protection where he spoke in damning terms about the church’s handling of child sexual abuse allegations.

The complaint against Coleridge relates to a 2006 meeting with a Canberra woman who had offered information about child sexual abuse within his then archdiocese of Canberra and Goulburn.

It is alleged he called the woman a “gossip” and acted aggressively towards her.

Coleridge strongly rejects the allegation. It is understood the investigation is almost complete.

In a statement, the archdiocese of Canberra and Goulburn confirmed it was investigating the matter, but said its progress had been delayed because the woman “chose not to engage with the process”. The archdiocese of Sydney and the archdiocese of Canberra and Goulburn were made aware of the matter several months ago.

“Discussions between the two archdioceses led to agreement that Canberra and Goulburn would establish an independent investigation of the allegations,” a spokesman said.

“Archbishop Mark Coleridge cooperated with the investigation and strongly refuted the allegations. When [the complainant] was invited to cooperate with the independent investigation, she chose not to engage with the process.

“She has instead chosen to take these allegations to the media, which is deeply disappointing.”

Guardian Australia has seen documents confirming the church has engaged a consultant, Kate Halloran, to examine the matter.

The announcement of Coleridge’s trip to the Vatican prompted the woman, who has informed Guardian Australia she does not wish to be named, to write to the archbishop on 20 December 2018, urging him not to go.

Coleridge delivered a closing sermon during Sunday morning mass at the conference.

He labelled the church’s care of survivors “weak” and urged clergy to “listen to survivors, but not just listen – to walk with them”.

“I’m talking very practical ways of accompanying all those who have been abused in whatever way they need to be accompanied,” he said.

Coleridge later told reporters there was no place in the church for abusers.

“It’s very clear now ... that anyone in the Catholic church in any part of the world who thinks that he or she can get away with sexual abuse of the young and vulnerable, has absolutely nowhere to go,” he said.