The Greens, who held six seats in the last Parliament, return with new additions Kevin Hague and Catherine Delahunty.
There is the possibility of a third, Kennedy Graham, depending on the number of special votes -- votes yet to be counted -- the party gets.
Co-leader Jeanette Fitzsimons said while she was disappointed that the political left was no longer governing the country, the party was in very good shape.
"Two more Green MPs and the possibility of a third will make a big difference to our capacity in Parliament, they'll make a big difference to what our caucus can achieve," she said.
"They're both amazing people.
"The special votes have always favoured the Greens, I will never forget 1999 when on election night we had zero MPs and when the specials came in 10 days later we had seven."
Ms Fitzsimons said this time the country had decided it wanted a change.
"It may not be quite sure what it has changed to, but it has changed and part of that change has come to us," she said.
"We will do everything we can to add value to the new government.
"We won't support it on confidence and supply, we won't support a National government, but we will work with them where we've got common ground to add value to the government of New Zealand."
Last election the Greens did not make it into government when New Zealand First and United Future refused to work with them, so Labour left them on the sidelines.
NZ First failed to win a seat and United Future leader Peter Dunne nearly did not make it either.
Labour's Charles Chauvel came close to taking Ohariu, and would have torn it from Mr Dunne had he secured the local Green candidate's 2229 votes.
Ms Fitzsimons said that was an unexpected situation, and no thought had been given to telling Green voters in the seat to support Labour.
"We haven't done those kinds of deals and trade-offs but we weren't even asked to," she said.
"I don't think anybody had any idea that Charles Chauvel was so close to Peter Dunne."
Green feelings about Mr Dunne were strong with one supporter saying "you filthy filthy thing" when his image loomed on a big screen over the gathering.
Another supporter, Aucklander Terry Payne, said parties had to make their own ways.
"The Greens wanted to work with Labour last time and got rejected, I'd hate to see that happen again."
He was happy with the Green's result despite polls having given the impression it would be better.
"It's a good increase, I'd like it to be more, it would be great if it was 10."
Greens campaign manager Gary Reese said the campaign had revitalised the party and rebranded it with a more professional image.
"It's actually boosted our morale and that will have real benefits after this campaign," he said.
"Everyone's feeling very good about who we are...You can campaign positively and be successful."
Mr Reese said it was likely young supporters who did not vote were responsible for the result being lower than expected.
"I think we are going to be the third-largest party in Parliament for actually the first time in history...I think that will give us an excellent platform to really build and grow from there."
Supporter Georgina Ellis was less upbeat.
While pleased the Greens were back she was unhappy with the bigger picture.
"I'm feeling quite depressed. (A National Government) makes me very concerned for our country...hey, how much damage can a government do in three years?"
Ms Fitzsimons, in her victory speech, touched on that concern -- that the environment and other Green concerns would not be a priority.
"I want to particularly thank all of the 6.5 percent who have stayed loyal to the Greens, loyal to the future of our children, loyal to the planet," she said.
"And I wonder if in 20 years time whether there will be people who look back at 2008 and say `I am really glad I voted for tax cuts rather than future of our children'."