Former world-rated boxing champion Sean Sullivan has become the first person to be sent to prison for ripping off Housing New Zealand.

Sullivan, once ranked the No. 7 welterweight in the world, was jailed for six months on Friday.

HNZ urged the Auckland District Court to impose a custodial sentence after Sullivan had earlier pleaded guilty to two fraud charges.

He was also ordered to repay more than $30,000.

Sullivan was first exposed in the Herald on Sunday in 2007 as the state housing tenant accused of subletting his taxpayer-subsidised home for a $77-a-week profit. It was revealed that Sullivan owned a holiday home in the Bay of Islands and was not eligible for HNZ help. Yet he managed to rent the Mangere home for $133 a week and then rented it out for $210.

Housing Minister Phil Heatley said the sentence was a warning to those who were ripping off the state: "We are in a position that there are too many genuine people on the waiting list needing housing and we don't want those who are defrauding the system."

Heatley was strident in pursuing the case while in opposition and said he was pleased to see it followed it through as minister.

HNZ said the case was among a large increase in prosecutions. There were 10 in 2008 and 62 so far this year.