People occupying the site at Ihumātao say it is unacceptable that police officers brought guns into the area.
Protesters are still occupying the South Auckland coastal site where Fletcher Building plans to build 480 homes.
A video is circulating on social media showing police carrying the guns a short distance.
However, police said the officers were only removing the firearms from two police cars behind the cordons at Ihumātao - and putting them into cars that were then driven off site.
The officers were not armed, but had access to firearms in case of an emergency, they said.
Despite that, the protesters said showing the weapons in public eroded the trust between thems and the police, and they were now renewing their calls to get rid of the police from the site.
Campaign spokesperson Pania Newton said they "should be chasing white supremacists, not Māori protectors".