KORAT, Thailand (AFP) - Twelve golds are up for grabs on the final day of track and field action at the SEA Games Tuesday as the footballers also take centre stage.

Thailand, looking unstoppable in their quest to dominate the medals table, lead the way on 79 gold -- just a handful short of their 2005 tally of 87.

Nearest challengers Vietnam are a long way adrift on 41 and Singapore lie third on 32.

The host nation's footballers, seven-times defending SEA Games champions, will tonight be looking to match the success of their track and field counterparts, who on Monday won five more gold.

On another day of record breaking, five Games marks were smashed in track and field, including in the men's and women's 4x100 metre relays, both won by Thailand.

However Thailand's success Monday was overshadowed by the expulsion of two of their athletes for failing drugs tests.

Highlights on the final day of athletics competition will include the men's and women's 200m and the men's and women's 400m.

Thailand's footballers are confident of winning their semi-final against Singapore as they bid for their eighth consecutive SEA Games title, after taking maximum points in group matches.

Coach Thongsuk Sampahangsit said his players could defeat ASEAN champions Singapore if they stuck to their game plan, the Bangkok Post reported.

But Singapore's Serbian coach Radojko Avramovic said his team would be fighting all the way and were a chance to upset the favourites.

"We have nothing to lose. We do not come here to give up," he also told the Post.

Unfancied Myanmar face Vietnam, who topped their group, in the other semi-final of the under-23 football competition.

Tuesday is also the final day of action in the pool with the women's 50m freestyle and the men's 200m freestyle races among the highlights.

The Sports Authority of Thailand said Monday that a male field hockey player and a female gymnast failed urine tests shortly before their scheduled competitions, and would take no further part in the Games.

The authority declined to reveal their names or the substances they were believed to have taken.

Eleven nations are chasing more than 470 gold medals in more than 40 sports at the 24th SEA Games, which ends Saturday.

Brunei, Cambodia, East Timor, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam are all taking part.