Sydney-based Servcorp is trialling co-working spaces at four locations – Sydney, Tokyo, New York and London – and Regus is using the Spaces brand to develop muscle in the new territory.

Servcorp chief operating officer Marcus Moufarrige said: "Co-working is a very fashionable term. We like to talk about flexible spaces and the flexible space area is growing immensely. It's not disrupting serviced offices. We are already disrupting traditional offices and we've been doing it for around 40 years."

"It's been successful in London and going OK in Sydney and New York," Mr Moufarrige said. "It's not the Uber of office. Uber doesn't have drivers or cars whereas even co-working spaces have to rent offices and pay staff."

A recent report by Knight Frank shows co-working spaces are expected to increase globally by another 25 per cent next year to 12,700 sites covering more than one million workers.

Sydney's co-working office sector has grown by 41 per cent a year in the past five years.

While Melbourne has more 152 sites totalling 58,880 square metres, Sydney has only 56 co-working spaces covering 44,182 square metres.

Knight Frank researcher Alex Pham said: "While the amount of space in Sydney is less than Melbourne, Sydney tends to have larger spaces."

Sydney co-working spaces average 789 square metres compared with a Melbourne average of 385 square metres.

"Given the relatively higher office rents and operating costs in Sydney, achieving economies of scale is critical for co-working space operators," Mr Pham said.

Mr Moufarrige said there's been a relatively low entry point in the market, especially in Australia, because office rents have been so cheap.

"In Australia, you can get a great incentive from landlords to take up space but after the incentive period is over and the rent increases will you have enough $200 a month members to pay $100,000 a month in rent? Landlords are pretty ruthless," he said.

Rents have been flat for a long period and incentives hovering at around 30 per cent but all observers are forecasting and end to that situation in the next 12 months.

Servcorp, which has 154 locations globally, receives pitches from co-working spaces looking for joint venture projects.

"In a year I've seen one that I think has a successful business model. The most successful co-working spaces are already offering serviced offices. It's not this communal wonderland," Mr Moufarrige said.

While a new co-working space seems to open every week in each city, serviced offices are seen as more corporate and traditional compared with the open working environments of co-working spaces.

Savills agent Phil Cullity says: "There seems to be insatiable demand from start-ups."

But other businesses and more mature businesses are looking for something else.

Knight Frank's Hamish Sutherland said: "I think there's always going to be demand for the traditional serviced offices. I don't think it will affect that it too much. "

A report by Capital Economics into the UK serviced office market, which is the biggest and most mature, forecasts a tripling of the value of the market from just under to £20 billion  to £62 billion largely because the financial, communication and information services sectors which most often use serviced offices are also the ones poised for expansion in the next 10 years.