The alleged shooter in Christchurch’s deadly massacre has described himself as “just an ordinary white man” and the shootings were revenge for “foreign invaders”.

Dozens are feared dead in the NZ city after a gunman walked into a mosque containing hundreds of worshippers and opened fire, live-streaming the horrific event on social media.

An incident was reported at a second mosque and police also found bombs attached to cars, which have now been defused.

The man, 28, who identified himself on a social media account, issued a 74-page so-called manifesto titled “The Great Replacement” and posted it on a message board website.

Multiple media outlets are reporting the shooter as Australian-born man Brenton Tarrant was the shooter, and one of four people in custody.

On forum site 8chan, an anonymous post dated March 14 contains a threat to “carry out attacks against the invaders”.

“If I don’t survive the attack, goodbye, godbless and I will see you all in Valhalla!”

The post directed people to a Facebook page linked to the man’s name.

In a manifesto posted online, he said he was born in Australia “to a working class, low income family”, and his parents were of Scottish, Irish and English stock.

“I had a regular childhood, without any great issues,” he wrote.

He said he worked for a short time before making some money investing in Bitconnect – crypto currencies having an outlaw history and bent – then used the money from the investment to travel.