Four and a half years after finishing second at the 2001 world championships, South Africa's 4x100 metres relay team will be awarded the gold medals.

The IAAF, the ruling body of athletics, has confirmed in writing a decision to retroactively reallocate the medals after a doping ban on American Tim Montgomery, Athletics South Africa said in a statement.

The United States, race winners in Edmonton in 2001, have been stripped of the title after former team member Montgomery was banned for two years last month and had all his results from March 2001 annulled.

The decision to award the golds to Morne Nagel, Leeroy Newton, Matthew Quinn and Corne du Plessis doubled South Africa's gold medal tally from the 2001 event.

Trinidad and Tobago will be awarded the silver medals and Australia have been promoted to third.

Montgomery, who never tested positive for a banned substance and has protested his innocence, was banned by the Court of Arbitration for Sport for offences related to the BALCO laboratory. Montgomery subsequently announced his retirement.