The United States has increased Cambodia's garment export quota to the US market by 15 per cent, largely because of improvements in factory working conditions, the Cambodian commerce minister revealed today.

Cham Prasidh announced on Thursday that earlier this week he had signed a three-year renewal of an existing textile agreement- unique in how it links labour conditions with trade to the US - with the US Ambassador to Cambodia, Kent Wiedemann.

He said a six per cent hike from base export levels of garments was boosted by a nine per cent bonus for improvements in working conditions, but while he welcomed the "significant increase" he added it was not enough to maintain the growth of the country's garment industry.

Garments are one of Cambodia's main export earners with the more than 200,000 workers employed at around 220 factories and producing brand names for clothing giants such as Gap, Banana Republic and Polo.

More than 70 per cent of that production, worth nearly $1 billion, is exported to the US market every year with that figure expected to increase even further in the future if Cambodia gains membership of the World Trade Organisation.