A former National Party president says the newest political party is staking out the genuine environmental space.

Sustainable New Zealand officially launched yesterday, with former Green Party member Vernon Tava as its leader.

Former National Party president Michelle Boag told Kate Hawkesby the existing Greens have taken a sharp turn to the left.

"They've made that very clear that they would not work with National, whereas Sustainable New Zealand is saying we will work with anybody."