Figures provided by the Valuer-General suggest the state government has in the past five years put aside about $150 million to compulsorily acquire about 1200 properties. And with the government planning further infrastructure projects, including a second Sydney airport, more compulsory acquisition letters are likely in the following areas:

 About 150 properties are forecast to be acquired for the NorthConnex and first stage of the WestConnex motorways.

 Internal planning documents show the state government is planning to spend about $240 million on property acquisitions for the light rail in the city and eastern suburbs.

The government also budgeted about $220 million for property acquisition along the north-west rail link corridor.

At present property owners are compensated for the market value of their properties, plus up to $25,000 for distress and reasonable costs of relocation.

Most landowners agree to sell to the state on a ''voluntary'' basis, and therefore fall out of the ''compulsorily acquired'' classification.

Over the past five years, only about 10 per cent of the Roads and Maritime Services property budget has gone towards compulsory acquisitions. A Transport for NSW spokesman said that only about 5 per cent of properties acquired for the north-west rail link corridor so far have been compulsory.

But Chris Johnson, of the Urban Taskforce, an organisation representing developers, said he expected the government would need to use more compulsory acquisitions to boost Sydney's density and support new infrastructure in a city that would need to build on top of itself.

"We have 1.6 million houses and in the next 50 years, we're going to have another 1.6 [million]," Mr Johnson said. "The city's going to have to change and that's likely to mean that more places close to transport nodes may well need to be acquired for the benefit of the broader public.

"In the medium-to-long term it's highly likely we're going to need development along places like Anzac Parade, Canterbury Road and Victoria Road.

"If we're going to get decent public transport along them, we're going to need [population] density to justify the transport."

Vince Mangioni, a senior lecturer in property economics at University of Technology, Sydney, published a paper this year about the expanding role of compulsory acquisition in redevelopment of our cities.

The state government performs about 80 per cent of acquisitions.

Dr Mangioni forecasts that councils are likely to increasingly use compulsory acquisition to make way for urban development, and to begin to use it for projects such as residential apartment blocks, rather than simply for making way for roads as they have in the past.

He said while the state government was largely compensating people fairly, changes to compulsory acquisition law should be considered to account for its increasing use.

"I think there needs to be some provision in there for reinstatement: putting somebody in as close to the same position as they were [before]," Dr Mangioni said.

Nearly 15 per cent of all people who receive compulsory acquisition offers from the RMS have taken the matter to the land and environment court seeking a better offer.

John Maston, a barrister specialising in compulsory acquisition law, said NSW law was generally fair and well applied, but the quality of value estimates could vary.

The government assists people to seek legal and valuation advice.

A poll a decade ago found 75 per cent of Australians opposed compulsory acquisitions.

After 30 years, council plans for car park drives family ouster

Chrystella Koutsoullis learnt the local council was planning to turn her family home into a car park when her daughter read it in the newspaper.

A small account of a February council meeting in the St George and Sutherland Shire Leader reported a council request for permission from the state government to compulsorily acquire two houses on Cook Street in Mortdale.

"I was very sad,'' the 74-year-old grandmother of 15 said. "I've been here for 30 years; my [six] children got married in this house.''

Mrs Koutsoullis and her husband, 80-year-old Charalambos, moved in about 1980, a few years after they arrived from Cyprus. They saved up and bought the house for $64,000.

When the council started making offers on her property she ignored them. At first a letter arrived offering $650,000. Months later, the offer had increased to $695,000.

"It's very close to … the train [for] when I want to go to the doctor. It would be very hard to go,'' she said.

The letters, she said, made no mention of compulsory acquisition.

Minutes show the council discussed the matter in closed session because of commercial-in-confidence concerns. The council resolved, pending state government approval, to start compulsory acquisition proceedings.

A council spokeswoman said compulsory acquisition was just one option it was exploring.