Greenpeace has apologised to Nigel Latta after he accused the organisation of harassing him with cold-calls.

The psychologist and documentary-maker said he received numerous "spam calls" from the New Zealand arm of the environmental organisation after he signed a petition in support of a Greenpeace campaign.

"Why, if you sign a petition, does @GreenpeaceNZ then constantly harass you with spam calls?" he wrote on Twitter.

"Multiple spam calls. Then you block … them and they call from a different number.


"Yet another example of an organisation that seems to have lost sight of its mission."

In response, Greenpeace said Latta would get no further calls and apologised to him.

The organisation said it called people who showed support for its work to update them and seek more support.

"That support is our lifeblood," Greenpeace said, noting that it did not get any funding from Government or businesses.

It also rejected Latta's suggestion that it had lost its way, saying it had a clear mission and was "in the fight of our lives" against "twin climate and ecological crises".

Consumer New Zealand says anyone receiving unsolicited calls is entitled to ask to be removed from an organisation's list.

"However, we get enough complaints to know you may have to ask more than once," it said on its website.

Nearly 15 per cent of New Zealanders in a Consumer NZ survey said they received unsolicited calls from charities at least once a fortnight.