Labour believes there is a link between the introduction of an 0800 phone line by Housing New Zealand and a rise in tenants failing to pay their rent over the past nine months.
The number of tenants behind with their rent rose by 783 from 8240 last July to 9023 at the end of March. Rent arrears were $5.3 million.
Labour housing spokesperson, Phil Twyford said the arrears increased steadily after the phone service was introduced last April.
"I think Housing Minister Nick Smith has got to take a really hard look at whether the 0800 number has worked or not," Mr Twyford said.
"They had the slogan that this was going to be smarter, fairer and faster. Well, it hasn't been smarter, it's not fairer and it certainly hasn't resulted in faster service."
Housing NZ acknowledges that the increased arrears may have been a result of a restructure at the agency.
But acting chief executive Kaye Read said rent arrears have been reduced to $1.7 million by determining where and why debt occurs, and by staying in touch with tenants about it.