South African double amputee sprinter Oscar Pistorius will not be allowed to compete at the Beijing Olympics because the prosthetics he uses give him an advantage over able-bodied athletes, the ruling body IAAF said on Monday.

The IAAF said in a statement from its Monte Carlo headquarters that Pistorius is not eligible to compete in any events run by the IAAF: meets, championships or Olympics.

Pistorius, 21, is expected to challenge the ruling made by the IAAF Council, based on an independent study by professor Peter Brueggemann of the biomechanics institute at the sports university of Cologne, Germany.

Tests with Pistorius and his so-called Cheetah prosthetics took place November 12-13, 2007. The "Blade Runner" Pistorius was also allowed to run at two IAAF meets last summer for study purposes.

"IAAF Council as been able to review the full report and has decided that the prosthetic blades known as cheetahs should be considered as technical aids in clear contravention of IAAF Rule 144.2. As a result, Oscar Pistorius is not eligible to compete in competitions organised under IAAF Rules," said the IAAF.

"It is evident that an athlete using the Cheetah prosthetic is able to run at the same speed as able bodied athletes with lower energy consumption ... An athlete using this prosthetic blade has a demonstrable mechanical advantage (more than 30 per cent) when compared to someone not using the blade."

The IAAF rule 144.2 outlaws the "use of any technical device that incorporates springs, wheels or any other element that provides the user with an advantage over another athlete not using such a device."

Pistorius, whose had to undergo below-the-knee amputations on both legs when he was 11 months old, had aimed to compete in the Bijing Olympics in August as part of South Africa's 4x400m relay team.

He won Paralympics gold over 200m in Athens 2004 and holds the amputee world records in the 100m, 200m and 400m. He frequently runs with able-bodied athletes in his home country.

Pistorius did not comment on the ruling Monday and - according to his agent Peet van Zyl - was discussing a possible appeal with his lawyers.

Pistorius said last Friday he would appeal any adverse ruling from the IAAF, the highest appeal body being the Court of Arbitration for Sport in Lausanne, Switzerland.

"I will not stand down," Pistorius said, claiming a responsibility on behalf of disabled athletes to "not allow one organization to inhibit our ability to compete using the very tools without which we simply cannot walk, let alone run."

He blasted as "premature and highly subjective" recent media remarks by Brueggemann, who told German newspaper Die Welt last month he felt Pistorius' blades gave him a "considerable advantage."

Pistorius said experts he consulted when preparing his response to the test results, which he submitted last Thursday, believed the data collected by Brueggeman "considers too few of the variables that need to be examined to make a decision of this magnitude."

"We strongly believe more tests should be done," said van Zyl. "His (Oscar's) dream is to be called an Olympian one day."

The South African Sports Confederation and Olympic Committee (SASCOC) said it accepted the IAAF's decision barring Pistorius from taking place in any IAAF-organized events.

"If the rules say he has an unfair advantage then it's an unfair advantage. We have to respect the decision," Mark Alexander, SASCOC vice-president said.

"That's what sport is about. Sport is a fair thing," he added.