However, he indicated he would vote accordingly if the party decided in support of gay marriage.
"At that point, we will make a decision as to what my views are going to be in the House. And I'll be comfortable with it at that point because Mana is bigger than me."
A bill on gay marriage is a conscience vote issue, rather than a party vote, but because Mr Harawira is Mana's leader and sole MP there is likely to be pressure on him to vote according to his party's wishes.
Party president Annette Sykes said the issue had to go through the party's policy process and would be discussed by local branches over the next three weeks before it was considered by the national executive in two months.
She supported gay marriage and had acted as a legal advocate for changes to the Marriage Act and Adoption Act for years.
However, there was a wide range of views among the party membership which had to be taken into account and the discussions so far were "vigorous" and wide ranging.
"We've got Destiny members debating with lesbians, debating with transgenders, debating with kuia and kaumatua. So we've got a huge spectrum of opinion that we have to try and take into account."
Maori TV's Te Kaea has reported one senior party member has threatened to leave the party if Mr Harawira will not support it. Another Mana member, Sue Bradford, said she strongly supported it but would not be drawn on what she believed Mr Harawira should do. Two MPs - Labour's Louisa Wall and the Green Party's Kevin Hague - have bills in the ballot to legalise gay marriage, although one will have to be drawn out to go before Parliament.
Mr Harawira was not in Parliament when the Civil Unions Bill passed - but did vote against a 2005 bill by former United Future MP Larry Baldock that would have defined marriage as being between a man and a woman, effectively ruling out gay marriage.
Since US President Barack Obama voiced support for gay marriage in May, Prime Minister John Key has said he supported it, as have Labour leader David Shearer and Maori Party co-leader Tariana Turia.
During an interview with Otago University political studies lecturer Bryce Edwards last September, Mr Harawira said he did not see marriage as an issue of human rights, whether it was between a man and woman or two people of the same-sex.
He defined human rights as the right to life, to food, shelter and water. "I don't necessarily know that it's a human right that a man and woman should be able to get married. That's not a human right - it's an accepted way of doing things, but it's not a human right."