By Tony Cheng BBC, Bangkok

The aim is to ensure that countries which signed up to a global agreement three years ago to end commercial child abuse are following their agreed plans.

Representatives of 20 governments will also look at preventing new forms of abuse such as the exploitation of children on the internet.

New technology provides new threats to children, says the organiser, the UN.

The internet, the ease of digital photography and mobile phones, all present new opportunities for abusers to sexually exploit children for commercial gain.

The success of commercial websites that now charge for access to child porn has simply added to a trade that has boomed in recent years.

This meeting is also aiming to incorporate the views of children themselves, many of whom will be represented.

Their first-hand experiences will be heard, as will their suggestions on how to tackle the problems of commercial sex abuse.

It is hoped that that injection of first hand experience and new thinking will provide an insight which could permanently combat the abuse of children for money.