Andrew Bree had qualfied for the Beijing Olympics

Swimmer Andrew Bree believes his positive drugs test was caused by him "unwittingly taking a stimulant" in an over-the-counter decongestant.

A statement issued by Bree's family on Wednesday night said that the Irish swimmer had "never knowingly taken a banned substance.

It added that Bree "abhors the use of performance enhancing drugs".

Bree registered an adverse finding for levmethamfetamine, which is contained in the US version of a Vicks Inhaler.

The substance is not contained in the UK version of the product.

US-based Bree is the only Irish swimmer to have so far qualified for this year's Olympics but his place in Beijing is now in doubt.

His family's statement added:"He will move to clear his name as quickly as possible so that he can continue preparations for the Beijing Olympics."

On Wednesday afternoon, Swim Ireland revealed that the County Down man was tested at the European Short Course Championships in Hungary in December 2007.

Swimming's European governing body (LEN) said that Bree had registered an adverse finding for levmethamfetamine.

Scottish skier Alain Baxter was stripped of an Olympic bronze medal in 2002 after using the same US version of the inhaler.

Skier Alain Baxter was hit by a three-month ban in 2002

However, Baxter received a three-month ban for the offence and was able to resume his career.

Bree will be hoping for a similar fate which would enable him to compete in Beijing.

Swim Ireland, the governing body of the sport, said on Wednesday that they had been informed of the test findings.

The Irish sports council say they have received notice of the positive test on an Irish swimmer from FINA, the world governing body.

It is believed Bree can now ask the FINA to analyse the B sample he gave to drugs testers or choose a hearing to argue his case, with the latter being the more likely scenario.

Bree is the only Irish swimmer to have qualified for the Beijing Olympics but cannot now take part in any competition until his name is cleared.

The Northern Ireland man clinched Olympic qualification in July 2007 when taking part in the 200m breaststroke at the US Nationals.

The 26-year-old broke the three-year old Irish senior record by achieving a time of two minutes 13.44 seconds.