A UN expert on housing says bold new policies are needed.

The public housing waitlist topped 15,000 households for the first time in January as new public housing places are overwhelmed by people in need.

A whopping 1581 eligible households added themselves to the waiting list in January, while just 581 were housed.

That led to growth of the overall waiting list to 15,235 - up from 14,869 in December and well over double the 6182 eligible families waiting at the end of 2017.

The median time to house someone has risen to 147 days from 132 in December, close to five months.

Meanwhile emergency grants for motel stays grew slightly with 3335 people receiving a grant, up from 3254 the month prior, but down on a peak of 3490 in September 2019.

MONIQUE FORD / STUFF The steady growth of the waitlist has been a huge point of political contention in recent years.

Auckland had the most eligible households waiting with 5597 on the waitlist, followed by Wellington, Waikato, and the East Coast.

The Government's build programme for state houses is just above its target, with 1298 public housing places built since the start of the financial year, above a target of 1290.

Less houses were built in January than planned - just 88 instead of 165, but this was made up for by the Government far exceeding its target in December.

KEVIN STENT/STUFF Public Housing Minister Kris Faafoi has argued that a new more welcoming stance from the Government is partially to blame for the huge waitlist.

The steady growth of the waitlist has been a huge point of political contention in recent years.

The Government has blamed the growth on both a lack of new supply during National's time in office and what it describes as a more welcoming approach to applicants, which has led to far more people asking for help.

"This Government said we would provide assistance to those who need it and this increase shows that people are responding to that message," Public Housing Minister Kris Faafoi said in January.

He has repeatedly noted that the total net number of public homes fell over National's time in office.

The Opposition has blamed rising rents for the crisis, which it in turns blames on new regulation of the sector which it plans to tear up if elected.

"Such a sharp increase in just two short years can only be explained by poor Government policy. Labour was too quick to meddle in the rental market when it should have been focused on building houses," National's public housing spokesman Simon O'Connor has said.

"The reason we're in this mess today is because KiwiBuild tanked, Labour's new rental standards scared off landlords at the affordable end of the market, and its decision to end tenancy reviews increased pressure on social housing supply."

Rents have risen in major urban centres steadily throughout the last decade. Between October 2017 and October 2019 the average rent in Auckland grew $21 from $545 to $566, compared to a rise of $28 in the two years prior.