Up to six people were reported dead when a gunman opened fire at a crowded mosque in the New Zealand city of Christchurch, during afternoon prayers on Friday.

The South Island city was placed in lockdown as police hunted for an “active shooter".

“A serious and evolving situation is occurring in Christchurch with an active shooter,” police said in a statement. “Police are responding with its full capability to manage the situation, but the risk environment remains extremely high.”

Unconfirmed reports said the shooter was wearing military-style clothing.

One witness told stuff.co.nz he was praying in the Deans Ave mosque when he heard shooting and saw his wife lying dead on the footpath outside when he fled. Another man said he saw children being shot.

“There were bodies all over me,” he said.

Local media said another mosque had been evacuated.

An eyewitness told Radio New Zealand he heard shots fired and four people were lying on the ground, with “blood everywhere”.

ESPN Cricinfo reporter Mohammed Isam said members of the Bangladesh cricket team, who are due to play a Test match in Christchurch tomorrow escaped from the mosque.

“They ran back through Hagley Park back to the Oval,” he tweeted.

Bangladesh's cricket team escaped unscathed after a shooting at a mosque in central Christchurch, an official told AFP.

Bangladesh Cricket Board spokesman Jalal Yunus said most of the team were bussed to the mosque and were about to go inside when the incident happened.

“They are safe. But they are mentally shocked. We have asked the team to stay confined in the hotel,” he told AFP.