Analyst Gartner says the number of data centres will peak this year, just shy of 50,000, but that by 2015 that will have dropped to around 45,500. Speaking ahead of the firm's infrastructure and data centre summit in Sydney next week, Phil Sargeant, research vice president said that he already knew of many large organisations which may have had five or six data centres which were now consolidating down to two or three.

While Australia has a lot of data centres, most are relatively modest in scale and there are only ten of Brobdingnagian scale.

These large data centres are defined by Gartner as having at least 1,000 racks of equipment and, or at least 20,000 square feet of space. Mr Sargeant said these were operated by Equinix, Global Switch, Fujitsu, IBM, HP, Polaris, Canberra Data Centre, CSC, Centrelink and the Department of Defence.

Mr Sargeant expected these already large data centres to continue to grow. He did not however expect any of the even bigger global data centres such as those operated by the likes of Google, Amazon and Microsoft to underpin their cloud services would emerge in the local market any time soon.

He did however think it was possible that in time these companies might consider taking space in one of the ten large data centres already in operation in Australia in order to have a local offering.

Just below that layer of massive data centre, Gartner says there are 90 large enterprise scale data centres  in Australia, each  with at least 250 racks of equipment and, or at least 5,000 square feet of space.

Mr Sargeant said that there was a great deal of consolidation going on in the market, and that more and more companies were looking to satisfy their ICT needs through a move to cloud computing.  The impost of the carbon tax would also have an impact.

'You get economies of scale in the big data centres and they can bring that to bear re their ability to purchase energy,' he said. 'They have better energy characteristics than smaller data centres.'