The New South Wales Government is selling public assets on a massive scale, offloading $1 billion worth of property in the past two years alone.

Office blocks, hospitals, schools and even an island are all up for grabs.

Some economists argue the state should hold onto its valuable real estate, but the Government insists the money would be better spent on new infrastructure and housing.

In 2011-2012, the Government sold state-owned assets worth $5 million.

In late 2012, it established a new agency, Government Property NSW, to identify and manage the state's lucrative real estate portfolio.

Agency CEO Brett Newman told the ABC the portfolio comprised 200,000 properties worth almost $130 billion.

Got a confidential news tip? Email ABC Investigations at investigations@abc.net.au For more sensitive information: Text message using the Signal phone app +61 436 369 072 No system is 100 per cent secure, but the Signal app uses end-to-end encryption and can protect your identity. Please read the terms and conditions.

"What we do is identify assets that don't need to be owned or are underutilised and we sell them so that the money can be reinvested in capital and improved services right across government," Mr Newman said.

Since April 2013, Government Property NSW has sold properties worth $1 billion.

They have included seven office blocks worth $400 million, the Ausgrid building in Sydney's CBD for $151 million, and justice precinct buildings in Parramatta worth $170 million.

It has also sold nine terrace houses in Millers Point for $22 million, and plans to sell another 293 of the historic properties.

The Government said the proceeds would fund new accomodation for the 58,000 people on public housing waiting lists.

The historic Bidura House and surrounding grounds at Glebe Point went under the hammer in December, selling for $33 million. Chinese developers hope to build up to 100 apartments on the site.

Also for sale is Peat Island and adjacent foreshore land at Mooney Mooney, on the Hawkesbury River, to make way for a housing estate, marina and retail hub.

Government Property NSW also wants to sell 99-year leases for two heritage-listed sandstone buildings near Circular Quay, earmarked for redevelopment as international hotels.

Part of plan to shift public servants out of CBD, says Treasurer

NSW Treasurer Andrew Constance told the ABC the big sell-off was part of a plan to shift public servants out of the CBD and reinvest the money into new housing and infrastructure projects.

"There's no point in us hanging onto the ivory towers which sit half empty when they're not being utilised in the interests of the community," Mr Constance said.

"We're not into a fire sale here, we're strategically managing our portfolio assets, based on the needs of in terms of the public sector."

Mr Constance said the Government was reinvesting the money in projects like a $300 million housing acceleration fund.

"It's designed to get the growth centres in this state moving with better local infrastructures. We're not going to tie up millions of dollars in taxpayers' money into property which could be better managed," he said.

"We have to utilise our assets more effectively in the interest of the taxpayer and as a result we've got a great strategy in terms of devolving decision making into the regions by shifting public servants out of the centre of town."

But Emeritus Professor of Economics at Sydney University, Frank Stilwell, said it was bad economic management for the Government to sell increasingly valuable assets at a time when it could borrow the money so cheaply.

"As a citizen it makes me angry and as an economist it makes me very sad because there's no great economic logic at work here," Professor Stilwell said.

"This is short-term interest being pursued against long-term interest of the people and I think people are smart enough to see that this is not a good economic strategy."

Professor Stilwell said the Government should be leasing underutilised buildings, rather than selling them.

"I think privatisation is inherently unpopular with the people and certainly the recent election in Queensland shows that the sale of public assets was a major source of electoral damage for the incumbent government," he said.

"The problem is in this case that the sale of real estate assets tends to be done in dribs and drabs and isn't therefore quite visible as the sale of electricity poles and wires for example.

"So it tends to be done rather out of sight, but as soon as the people come to see what is happening then I think one can expect that they will see it as bad economics, substituting short-run revenues for long-term economic management."