Leaked emails show Weta Digital staff in Wellington expressed concern about being asked to go and support the campaign launch of a mayoral candidate financially backed by Sir Peter Jackson.

The messages show some replied to an all-staff message - saying they weren't sure it was ethical for the company to be suggesting staff support Andy Foster's campaign launch last month.

The launch was at the site of a controversial housing development proposed for Shelly Bay on the Miramar Peninsula - which both Sir Peter and Mr Foster strongly oppose.

The initial message from a senior HR manager at Weta said an announcement was being made at Shelly Bay, that a new candidate would be running for mayor against incumbent Justin Lester.

It said Sir Peter Jackson would be there to support the candidate and was hoping for the support of those in Weta Digital who were passionate about the Shelly Bay issue, and other issues, like pest control.

It said transport could be arranged, and Weta T-shirts made available for those keen to go along.

"We would love as many people from Weta to join us at Shelly Bay at 4pm."

To which staff replied:

"I really need to know who the person is before I 'show up in support'."

"I'm not entirely sure it's good practice to 'encourage' workers to support any political candidate or to use a private company name for that purpose."

"Forgive me but there could be a perception that it seems highly unethical for the head of HR to be pushing a political agenda in the workplace on behalf of the company owner."

But some were surprised by these responses, saying:

"I'm not sure why there's so much concern about this? It's an announcement from the owner of the company you're working for that's clearly asking those people interested."

Mr Foster said he knew emails were being sent out generally to people in Wellington to rally support for the mayoral launch - which was rather last minute, on a Friday afternoon.

"I was asking a few people to go down there as well, so it was all done fairly late in the piece, and obviously people are entitled to come down or not come down as they choose. I think we still live in a democracy."

Mr Foster, who's a councillor in the Onslow-Western Ward, said the 100 to 150 people who did turn out to the launch were concerned about Shelly Bay and the Miramar Peninsula.

"People turned out because they were really concerned about Shelly Bay, there's a lot of people in the eastern suburbs, in fact across the city who are really passionate about this, and they're really upset by the really terrible council process around it.

"So this is about a special place, and bad process."

Mr Foster wouldn't say if he knew the emails were going specifically to Weta staff.

Mayoral candidate Diane Calvert said Sir Peter Jackson had the right to ask staff if they wanted to go to the launch.

She said people who supported her mayoral launch, did so because they believed in her.

"Wellingtonians need a mayor who's not in the pocket of the Beehive not in the pocket of any one person, they want someone who will represent all Wellingtonians - and that's me."

Another candidate, Conor Hill, said it was obvious Mr Foster was tied to Sir Peter Jackson.

Mayor Justin Lester, who's in the running for a second term, said it was not a discussion he wanted to get involved in, but Weta staff had been in touch and raised their concerns with him.

Employment lawyer Peter Chemis said there was no harm in an employer asking their employees to come along and support a cause they were interested in.

"It was simply a suggestion that they could go if they wanted to, they weren't required to support the candidate they were told to come along if they were passionate about the issues. All of that is fine.

"If the employer gets pushy and says 'you must go and I want you there', that's probably unlawful."

Mr Chemis said while it was a political event - it would only be an issue if the email had asked staff to support Mr Foster - or else.

Weta did not respond to requests for comment.