SYDNEY'S property market has stepped up to the world stage with inner-city prices topping those in Manhattan, Paris and London and uninhabitable hovels in the inner west fetching up to $800,000.

As the popularity of city fringe suburbs like Paddington, Darlinghurst and Surry Hills soars, some local listings are fetching more than $13,000 per square metre - pricier than lifestyle hubs in Manthattan, Paris, Hong Kong and London.

A dilapidated Newtown terrace with rotting carpets and holes in the ceiling, bequeathed to the RSPCA, sold at auction for $800,000.

Former London real estate agent and now host of Foxtel's Selling Houses Australia Andrew Winter said within just a decade Sydney has appeared on the international property stage.

"Years ago there was no comparing London and Sydney prices. But now despite what really is a minute population, Sydney is up there on the top 10 list of residential cities," he said.

"Sydney has become a 'lifestyle city' with people coming from all over the world to call it home. Even if they don't just work in Sydney, it has become a base for many international residents.

"Interestingly, when you look at these inner-city Sydney suburbs where prices now compare internationally, many of the homeowners have lived at some point in London, New York or Hong Kong, so they know what real estate can cost."

Sydney buyer's agent Patrick Bright said while other global cities market property with a price per square metre, or foot, Sydney real estate agents do not, making it hard for buyers or sellers to know what Sydney is worth by the metre.

Mr Bright said lifestyle, location and view all came into play with Sydney real estate and when all those elements combined it lifted local property prices to international levels.

"I think that's why auctions work so well here, because you might have an idea of what a property is worth, but when there's a stunning view of the water, emotion kicks in and the price goes up," he said.

The theory held on the weekend in Newtown where 27 registered bidders did battle for a three-bedroom Denison St property with rotten carpets, stained and peeling wallpaper and sunlight streaming through the upstairs ceiling, which had been marketed with price expectations of over $650,000.

Zanita Morgan's winning bid raised $800,000 for the RSPCA after the property was left to the animal charity in the former owner's will.

She said she and her husband, who bought the house with friends, planned to renovate and on-sell.

Last month, a 34sq m unrenovated studio in Elizabeth Bay attracted 42 registered bidders at auction and sold for $462,000, or $13,588 a square metre for a single room.