Ms Collins said she couldn't see the offence in the tweet.

"I think gay's pretty normal, isn't it? Why would anyone be offended at being called gay?" she told Newshub.

When asked whether she believed the tweet inferred gay people are not decent and hardworking, Ms Collins said that wasn't her interpretation.

"That's not what I thought at all. Not at all. Everyone knows I'm very pro-gay, so if anyone's taken offence, I apologise, but I certainly never meant any offence."

"I wouldn't have seen anything wrong in gay people being gay. That's just the way it is," she said.

She said she does not believe gay people are like a "virus".

"I would be very upset if people were offended, because I certainly didn't mean to offend people."

Rainbow Youth Executive Director Frances Arns said it is disappointing that Ms Collins liked the tweet.

"The suggestion that queer people are a parasite on our society is hugely disappointing. To see leaders in our country, like Judith Collins, supporting this kind of messaging is really sad," Ms Arns said.

"We need to be creating positive and uplifting dialogue about the diversity of sexuality, and showing our rangatahi that they can be whoever they are, and not be treated like a 'virus'."

In May, National leader Simon Bridges told Newshub he was "regretful" after he 'liked' a tweet which mocked Prime Minister Jacinda Ardern's partner Clarke Gayford. The tweet showed him wearing a dress.

Ms Collins' tweet is reminiscent of a moment in 2011 when then-list MP Damien O'Connor described the Labour Party list as run by "self-serving unionists and a gaggle of gays".

Mr O'Connor, who is now Minister of Agriculture, had to apologise to then-party leader Phil Goff and to the entire Labour Party caucus.

Newshub.