Actress Lucy Lawless is heading back to the United States and straight back to work after two months of lending support to the Greens.

Lawless was the first celebrity supporter to show up at the Greens' election night bash at the Hopetoun Alpha hall in Auckland tonight.

"Helping out during the campaign has been thrilling, but I have to get back to America and resume that frivolous thing I call my career," she said.

Lawless said her next acting role would be in television and would be "exciting" but insisted she had been "sworn to secrecy" about details.

Lawless, who tucked into a plate of wild wheat bread and pumpkin humus, said she intended to party the night away at the Greens HQ. "I'm pacing myself because its going to be a long night, but I'm hoping there will be some karaoke on the go."

The actress said she found being involved in campaigning to be absorbing but added she wouldn't be getting further involved in politics at this stage. "I have never been so excited or inspired before," she said. "my dad did once stand for National, so perhaps that is where I get my interest in politics from.

"The whole experience has been absorbing and every day it has been one punch after another. It has been very dramatic, and being an actress, I like that.

"As far as I am concerned the Greens are the party of the 21st century. It is the only party taking climate change and equality seriously.

"I have been so impressed with the generosity of the people who have been standing through the giving of their time and their service, but I don't see myself getting further involved due to the amount of time required."

Other celebrities expected to attend the Greens election night party included Anika Moa, Julia Deans and Keisha Castle-Hughes.

Lawless is currently filming the superhero TV series Marvel's Agents of Shield.