A man in military clothing has been arrested after shootings at two mosques this afternoon.

A photograph shows a man kneeling on the footpath outside Papanui High School, with his hands behind his back.

A gun can be seen on the footpath in front of him.

Corban Manson, from Christchurch, said he saw police arresting the man when he was driving past this afternoon.

"I was just on my way home. The guy was on the footpath with the cop and has his hands behind his back.

"There was a camo gun sitting right under him, which looked like a rifle. He was in full camo as well."

Police had blocked off the road either side of the high school.

About 3.30pm, a staff member at the school said it had been locked down and staff were hiding under desks.

She could not comment further, saying it was unclear what was happening.

Police arrest a man a Papanui High School. Photo / Supplied

Unverified video shows two men with guns near the school gates.

A photographer at the scene, Joe Morgan, said armed police rushed into the school about 3pm, before rushing out again.

They then re-entered the school before re-emerging again, walking this time. Morgan said ambulance staff were then called in.

According to school communication app Skool Loop, at least 28 schools were in lockdown.