A Christchurch woman is furious a flyer from the group Voices For Freedom ended up in her letterbox.

It contains nine claims about Covid-19 and the vaccine, and asks readers "are you fed up with Covid yet?"

The leaflets have been making their way into letter boxes around New Zealand, including Tauranga.

The woman, who RNZ has agreed not to name, said she had health problems that put her at serious risk of dying from Covid-19.

She is now fully vaccinated, and says she jumped at the chance to do it.

"My doctors have told me it's what I should be doing, my specialists and all the people that take care of my health," she says.

"I have a big team because my condition is rare and really severe and they've all told me to get it done."

In a statement, Voices For Freedom says "over 500,000 Fed Up Flyers have been printed and distributed nationwide by thousands of Voice For Freedom supporters".

Associate Professor at the University of Auckland and vaccinologist Helen Petousis-Harris says the flyer is misleading and contained a lot of emotive language.

"Such as 'banned' and 'we're not allowed to know' and 'health authorities are ignoring this' and 'experimental'," she says.

"So those are all sort of things that provoke an emotion, and the statements are sort of quite vague.

"But it leads you to kind of think that 'maybe there must be some conspiracy going on here', so it's very misleading."

Dr Petousis-Harris points to several claims in the flyer, including one stating the Pfizer vaccine is experimental.

"The vaccine completed it's efficacy and safety assessments and there were no steps missed," she says.

"As with all vaccines, studies can go on for sometime after that to make sure you use those very precious participants for as long as you can."

Petousis-Harris says vaccine studies are always in play when products were being used, and studies would always be going on.

"It's not experimental. I think that's deeply misleading," she says.

"It's authorised all over the world and hundreds of millions of people have received it, so many lives have been saved."

Petousis-Harris says people need to be very careful when researching the vaccine and seek information from places of expertise, like research institutes.

The Advertising Standards Authority confirmed it had received three complaints about the flyer.

It has also received a complaint regarding a separate mask leaflet also printed by Voices For Freedom.

-RNZ/Katie Todd.