Gay Catholic groups want the Pope to do more than just apologise for how the Church has treated LGBT people, asking for action to follow his recent comments on the matter.

The Pope addressed reporters on his journey back to Rome from Armenia on Sunday, saying that Christians must seek forgiveness from gay people for the way they had treated them.

"We Christians have to apologise for so many things, not just for this [treatment of gay people], but we must ask for forgiveness, not just apologise! Forgiveness! Lord, it is a word we forget so often!" he said.

"The questions is: if a person who has that condition, who has good will, and who looks for God, who are we to judge?"

He also recalled the Church's teaching that gay people "should not be discriminated against. They should be respected, accompanied pastorally."

The executive director of a leading organisation for LGBT Catholics, DignityUSA, said that the Pope's statement was powerful, but was not enough without subsequent action.

"For a pope to acknowledge that the church has done so much damage to gay people, and that we deserve an apology, is an unprecedented act of humility," Marianne Duddy-Burke told the New York Times.

"But a statement of remorse is only as good as the change in behavior that follows."

Duddy-Burke cited cases of gay employees being fired by Catholic schools in the US after they married in civil ceremonies.

"We need the church to understand the reality of our lives," she said. "And where church teaching and practice has caused so much trouble."

Her sentiment was echoed by Ryan Hoffman, co-executive director of Call to Action, another Catholic activist group. He praised Francis' remarks, but reiterated that Catholic officials must "reform teachings and practices that refer to gay people as 'objectively disordered' and intrinsically evil'.

"It's time Francis' wise words translate into just action," he said.