Social services minister Kevin Andrews has asked organisers of the World Congress of Families conservative Christian conference to remove a reference to him as “international secretary” from their promotional material.

Andrews last week pulled out of delivering the opening address at the World Congress of Families after hearing that the rightwing Christian group Catch the Fire would host it.

In the latest congress newsletter, the anti-gay, anti-feminist and anti-abortion group names Andrews as its international secretary. Previous newsletters have referred to him as “frequent WCF speaker” and “international ambassador”.

Andrews has been involved with the organisation since 1997, attending and speaking at several of its events.

Despite this, he has not listed his involvement with the congress in the parliamentary register of members’ interests, which requires declaration of “membership of any organisation where a conflict of interest with a member’s public duties could foreseeably arise or be seen to arise”.

Andrews does declare his participation in a Cancer Council charity event, being a guest at an international families conference in Rome and his membership with the Southern Masters Cycling Club.

A spokeswoman for the minister told Guardian Australia: “The minister does not hold any roles with the World Congress of Families. He was ‘ambassador’ for the WCF’s one-day congress in Sydney in May 2013 only.”

She said his listing as international secretary was an error by the congress.

Last month the organisation named Andrews its “Natural Family Man of the Year”.

Senator Larissa Waters, the Greens spokeswoman for women, said the community deserved to know whether their political representatives endorsed the World Congress of Families.

“This organisation campaigns internationally to criminalise lesbian, gay, bisexual, intersex, transgender and queer people and to prevent women from having abortions, even when their lives are at risk,” she said. “The World Congress of Families’ anti-choice, anti-gay, sexist agenda is horrifying to the majority of Australians.”

Members of parliament were required to list their involvement with organisations when they were an officeholder or had donated more than $300 a year to that organisation, Waters said.

“That our minister for social services supports this organisation is alarming and the extent of his support needs to be transparent, whether or not it is required to be listed on the register of members’ interests,” she said.

An organiser of the Melbourne congress, Babette Francis, said she had been asked by the minister’s office to remove references to him as international secretary from their materials.

“It was put there accidentally,” she said.

When asked when the congress was told to remove his association with the title, Francis replied “I don’t know”.

Andrews’ office also would not say when he became aware of the error and asked for the materials to be changed.

The annual World Congress of Families, held on Saturday in the south-east Melbourne suburb of Hallam, was marred by protests and featured a lineup of controversial conservative speakers.