Jacinda Ardern says protesters who gathered outside a new Christchurch high school she was opening had "no effect" on the event.

The Freedom and Rights Coalition organised the protest, sharing the details on social media with the title: "Emergency Protest 1".

About 50 protesters showed up outside of the new Te Aratai College in Linwood, waving flags and signs as cars toot in support drive by.

Ardern spoke to media about the incident saying it had zero effect on the visit.

She said she is not worried about protesters showing up to events she attends.

"No, because it isn't wherever I go. Look it's from time to time but it very rarely has any impact on the events themselves we are a part of.

"It would be a shame to let it detract from, for instance, what was otherwise a very lovely day with a group of school students excited about the reopening of their brand new school."

Ardern arrived at the school through the back entrance and managed to get inside undetected before 11am.

Earlier, protesters could be heard yelling "shame on police" and "give us our jobs back", while others shouted, "you have destroyed our lives".

Signs read "Human Rights Violations", "Unagenda is the work of Satan" and "$55 million of Media Corruption".

The Freedom and Rights Coalition is behind the event, sharing the details on social media with the title: "Emergency Protest 1". Photo / George Heard

A heavy police presence can be seen outside the school.

It is not the first time protesters have shown up to a school in Canterbury while the PM is visiting.

Ardern was at Tuahiwi School in February and things turned sour when she was leaving.

Protesters lined up outside and screamed things like "shame on you" and "murderer".

Police were called to the scene and dispersed the crow.

- Georgia O'Connor-Harding, NZ Herald