Scores of people had gathered at Chifley Tower in Sydney's CBD for an art auction hosted by online start-up Fine Art Bourse, created by Tim Goodman, a former chairman of Sotheby's, and Adrian Newstead, the founder of Cooee Art.

Buyers were competing for more than 80 artworks, including Emily Kame Kngwarreye's Earth's Creation I, which was expected to fetch at least $2 million.

But the auction was postponed after what was described as "an unusually high surge of traffic" overloaded the auction site's server, which is based in Hong Kong.

William Ehmcke, a director of the online auction house, said in a statement on Thursday that the timing and size of the attack suggested it was paid and deliberate.

"There is also evidence that the auction platform database was hacked, just prior to the auction launch, to further disrupt the sale process," he said. "All client data has now been removed from the FAB (Fine Art Bourse) database."

Mr Goodman said: "Someone out there does not want us to succeed."

On Wednesday, the company's IT project manager Carl Welsby said: "The flood of interest on the site resulted in over 170,000 server processes at once, meaning the server had to put all these requests and users in a queue to process, causing the web page to stop loading."

Mr Welsby might have expected stern words from his bosses over the embarrassing computer fail, but Mr Goodman suggested sinister forces might have derailed the auction, which has been rescheduled to Thursday.

"We are trying to find the source of the people that logged on at 6pm that caused the overload to the server," Mr Goodman said. "More specifically we are looking to determine if there is an unusual number of people logging on from one particular country.

"At 6pm, we had 60,000 cached requests. The web server did not crash but as a result of this massive traffic it took too long to serve requests so to the general public it appeared like a crash."

Asked who he suspected of the alleged IT mischief, Mr Goodman said: "I don't believe it to be an auction house. I suspect a dealer in Aboriginal art or an auction house aggregator. The former is more likely than the latter. The art business is competitive and can be cut-throat especially when the stakes are high just like any industry."

Mr Goodman later conceded it might not be sabotage. "However, 1000 people all logging on within minutes of each other seems very odd, hence our investigations," he said.

But one art commentator told Fairfax Media: "Well, of course they are trying to maximise publicity for their gig and if it looks like sabotage rather than their own IT stuff-up then someone else is to blame I suppose. They must have been very pissed off, that's for sure."