Advance NZ has been asked to not use a "misleading and irresponsible" advertisement claiming COVID-19 vaccines will be compulsory.
A brochure distributed by the party said: "Stop the attack on Kiwi freedoms by removing laws that force mandatory testing, mandatory vaccinations, and forced entry into homes without a warrant."
The person who complained about the brochure to the Advertising Standards Authority (ASA) said they were "concerned the advertisement was misleading and irresponsible as there is no such law forcing mandatory testing or vaccines".
The complaint was upheld.
The ASA said the claims for mandatory vaccines were not "substantiated".
"The complaints board upheld a complaint about the flyer advertisement for the Advance New Zealand Party and the New Zealand Public Party. This is because the reference to mandatory vaccinations in the advertisement had not been substantiated and its use to support statements about Government overreach in the response to the COVID-19 pandemic was not socially responsible."
Advance NZ, set up by former National MP Jami-Lee Ross, and the Billy Te Kahika-led Public Party are contesting the 2020 election together.
The ASA's decision also said Advance NZ's statement on supposed mandatory vaccines is "misleading".
"This is because the reference to a current law requiring mandatory vaccinations had not been substantiated by the advertiser," it said.
"The board also noted the COVID-19 pandemic has resulted in heightened fear about vaccination and the use of the unsubstantiated statement was likely to cause fear or distress without justification."
The ASA said this specific Advance NZ advertisement is not to be used again. Advance NZ has ignored ASA rulings in the past - they're not binding. The ASA didn't receive a response from the party in relation to the complaint.
Newshub has contacted Ross for a response.