Housing New Zealand is anticipating delays to its service when it switches to a new computer system next month.
The corporation will on Wednesday begin transferring 83 million records from its old systems to a $92 million new one.
Housing New Zealand came under fire this year when it closed several of its offices to walk-ins, and told people to call an 0800 number instead to get a more efficient response.
The changes resulted in waiting times of up to an hour before calls were answered.
Housing New Zealand general manager Philippa Jones says they're expecting similar waiting times when the new computer system goes live in August.
She says staff are well prepared and trained for the significant change and is asking people to be patient during the introduction of the new system.
"We're expecting that bedding-in period to take a month, maybe six weeks."
Ms Jones says the new system focuses on meeting the needs of tenants rather than just the letting and maintenance of properties.
Labour MP Annette King says after what she calls the debacle of Housing New Zealand's new 0800 number she is disappointed it isn't making more of an effort to prevent further delays. Housing Minister Phil Heatley is not commenting.
Meanwhile, a South Auckland emergency housing provider, Monte Cecilia, is worried the computer system switch could put further pressure on its services.
Monte Cecilia Housing executive David Zussman says when the 0800 number was first launched in April, the organisation experienced a huge increase in the number of families seeking assistance.
He says they do not want to see another wave of applicants because of new delays at Housing New Zealand's call centre.
Housing New Zealand says it has contracted an extra 20 people to handle calls and another 100 to manage the transition.