Welfare watchdogs on Tuesday said working conditions in clothing factories in Cambodia are showing "encouraging signs of improvement" with no evidence of child labour or sexual harassment and better pay and overtime.

The International Labour Organisation said its monitoring of 30 of the country's 220 garment plants that produce apparel for export to the US, Europe and other developed countries had revealed better conditions for the factories' 21,000 workers.

The Geneva-based group said in a statement that payment was still a problem in some plants buy many had implemented some of its suggestions and if that continued, there was "room for optimism that the working conditions in those factories will further improve".

The ILO monitored the factories as part of an agreement with the US that promises Cambodia extra textile exports in return for guaranteeing greater respect for workers' rights and better working conditions.

"We are pleased to note that this ILO project is directly contributing to the improvement of working conditions for Cambodian garment workers," said Juan Somavia, the ILO director-general.

"This provides sound support for one of the ILO's basic tenets, that employers, workers and governments can work together for the benefit of all concerned."

According to the Cambodian Development Resource Institute, Cambodia's garment industry employs more than 200,000 mostly female workers who last year produced apparel for export worth around $1.1 billion, of which $820 million was destined for the US.