The Whānau Ora Commissioning Agency is seeking a High Court injunction for the Ministry of Health to release data regarding Māori vaccinations.
The request will be filed in the Auckland High Court by 2pm on Thursday.
The agency wants Māori NHI info so vaccine providers can directly contact unvaccinated Māori.
John Tamihere, who is part of the group filing the injunction, said "It’s a sad day when you have to take legal action against your own mob".
When asked about the injunction at Thursday's media conference, Covid-19 Response Minister Chris Hipkins said the Government was trying to provide as much information as possible.
"We're working as hard as we can to provide as much data as we can, consistent with privacy laws, and that's with our Whānau Ora providers," Hipkins said.
"We've been able to provide them with more information but ultimately Government does have to follow the law here, and there are some laws around what we can and cannot do."