The New South Wales government has built two public housing units for every property it has sold, new figures show.

More than 900 government-owned properties have been lost and replaced by 1647 since 2014, figures obtained by Labor under freedom of information laws revealed.

It shows the government sell-off of valuable land in central Sydney suburbs like Millers Point and The Rocks had increased the state’s housing stock by just 745 properties.

The waiting list for government housing is 10 years in parts of the state, with a shortfall of more than 55,000 properties.

The Family and Community Services (FACS) figures show the government last year rid itself of 357 properties. That includes 282 sold to private buyers and 72 turned into community housing. Meanwhile, 522 new dwellings were built.

The properties were sold off to increase the housing stock by redirecting the funds from sales into constructing more affordable homes in the outer suburbs and regional areas.

At the end of March this year, 294 properties in Millers Point, Dawes Point and The Rocks were sold for a total of $546 million.

The terraces in Millers Point sold for about $2 million each, according to Property NSW, which is managing the sell-off on behalf of FACS.

They have been replaced with just 20 units in central Sydney, in Woolloomooloo. A further 12 have been built in Strathfield in the inner-west, along with nine in Lane Cove in the north shore. The rest have gone to the outer suburbs and regional areas like Coffs Harbour, Lake Macquarie and Wollongong.

Social Housing Minister Pru Goward said the Millers Point, Dawes Point and The Rocks properties were “ageing, tired and not fit for purpose as social housing”.

“We have been able to build new, modern, airy homes with every single cent which has been raised from the sales,” she said in a statement to The New Daily on Monday.

Ms Goward said the Millers Point properties would fund more than 1500 new homes, or about four or five new homes for each sold.

NSW had the largest social housing building program in the country, she said.

“Under the government’s Future Directions for Social Housing strategy, up to 27,000 social and affordable housing dwellings will be delivered over the next 10 years to reduce wait times.

“As projects from the government’s social housing building program come on line, the net increase in social housing dwellings will continue to gain ground.”

Shadow social housing minister Tania Mihailuk said the state government had failed to grapple with the housing challenge.

“The minister [Ms Goward] has repeatedly tried to justify the sale of public housing by saying she will build more – but she’s nowhere near meeting demand and almost isn’t making up for the ones she’s sold,” Ms Mihailuk said in a statement on Monday.

“It’s economically irresponsible and short-sighted to rely solely on existing housing sell-offs to fund future public housing, but that’s what the Berejiklian government is choosing to do.”

The iconic Sirius building, overlooking the Sydney Harbour Bridge in The Rocks, is also up for sale after a lengthy battle to save it.

Homelessness NSW pointed to ABS Census data released earlier this year, which showed homelessness had increased from 28,191 in 2011 to 37,715 in 2016.