Radio Sport commentator Bryan Waddle, who is at the Hagley Oval, very close to the Al Noor mosque, is reporting that staff at the stadium have told them to remain where they are after "a new incident".
New Zealand historically has had only a handful of mass shootings events.
One man said the scene at the mosque was chaotic.
She said police were working to get the situation under control.
Police also confirmed "there have been a number of fatalities" without giving a specific number.
Armed police have been deployed after reports of shots being fired at a mosque in Christchurch. The gunman is believed to still be at large.
Several minutes after they were barred from getting off the bus, the players escaped and ran through Hagley Park.
Armed police patrol outside a mosque in central Christchurch, New Zealand, Friday, March 15, 2019.
A witness told NZ news website stuff.co.nz that a man came in with an automatic rifle and started shooting people.
"I'm not now in a position to confirm casualties or injuries".
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Another witness told TVNZ that he heard two shots then he ran out the door.
"When I heard that there is a shooting - the sound whats coming".
"I spoke to one of them shortly after [the incident]".
"There were bodies all over me", he said.
"The floor. There's lots of blood on the floor, you can see when you go in".
Shootings were reported at the Al Noor Mosque, the Linwood Masjid mosque and Christchurch Hospital.
Local media said there were multiple casualties at one mosque and said another had been evacuated, and there were reports that members of the Bangladesh cricket team were also present at one site.
Peneha said he went into the mosque to try and help: "I saw dead people everywhere".
Among those inside the mosque in downtown Christchurch were members of Bangladesh's national cricket team, according to a Bangladeshi journalist, Mohammad Isam.
Parts of the central Christchurch area have been locked down. Police urge anyone in central Christchurch to stay off the streets and report any suspicious behaviour immediately to 111.