Scammers are trying to cash in on the Christchurch mosque massacres, using phishing emails with links to fake bank accounts to ensnare people keen to donate, New Zealand's cybersecurity body said Monday.

The attack on two mosques in which 50 worshippers were killed, allegedly by a white supremacist, has caused an outpouring of grief and prompted a flood of donations -- well over NZ$7 million (US$5 million) -- to those affected.

But CERT NZ, a government agency that responds to cybersecurity incidents, said emails with links to fake banking logins or fraudulent accounts were being sent out requesting money following the tragedy.

Westpac New Zealand bank warned separately in a statement that scammers were sending emails under its brand to swindle money out of people.

The warning was posted on Facebook, where the scam drew a furious reaction from users.

"Disgusting these low lives are trying to scam money out of people when they're most vulnerable," wrote one.

"What a shameless act," wrote another.

Some NZ$5.8 million has been donated via online fundraising platform Givealittle, and a second -- Launchgood -- has received more than NZ$2 million.

Forty pages have so far been set up on Givealittle to bring in donations to help those affected by the mass shooting, Robyn Lentell of the Spark Foundation that runs the platform was quoted as saying by the New Zealand Herald newspaper.

New donation pages are "popping up every hour", she said, adding each was "extensively" checked and had warning signs posted if they had not yet been moderated.