Mr Mark gave details in Parliament of the allegations. Cabinet Minister Phil Goff responded he would be willing to investigate the claims.
"I would be very concerned if the information contained in that email is correct; that corporate people are facilitating the laundering and banking of money by gang members."
The email released to NZPA was written by a man who said he used to be a corporate banker.
"It's not common knowledge but most of the major gangs are corporate customers (the biggest and best) of the trading banks, with their own managers, exchange and money market dealers, enjoying risk grade A (the best) interest rates. And their key staff enjoy preferential services and interest rates too."
The man said that in the late 1980s and early 1990s when only major companies could afford financial information services such as Reuters, which gives up to the minute foreign exchange and shares information, "the Mongrel Mob was so equipped".
"Of course gangs run legitimate operations, which presumably are fantastic ways to launder money."
He said far tougher measures were needed to get at the money behind organised crime.
Mr Mark said life should be made difficult for gangs by outlawing them and have high level investigations into the money side of organised crime.
Mr Goff said the Government was watching closely how effective the serious and organised crime legislation that had just come into effect in Australia was.
He said the Government had tightened controls on financial institutions to clamp down on money laundering and taken other measures.
The email writer said he had had to move his business because of a Headhunters gang pad next door.
