Hong Kong is exhibiting some of the world's most expensive jewellery items, with price tags up to HK$50m each, at the world's biggest gem fair.

The Hong Kong Jewellery and Gem Fair will feature several multimillion dollar pieces according to the fair organisers.

The event runs between September 21-27, bringing together more than 3,000 exhibitors from 44 countries.

It will include the largest-ever diamond pavilion as well as exhibitions of raw materials and other precious gems.

Most than 1,200 exhibitors are from Hong Kong, with over 300 from Thailand, and the Chinese mainland, Italy and the US also well represented.

The fair is expected to benefit from the economic rebound and pull in buyers wishing to replenish stock in time for the holiday season, as well as private collectors and designers.

"The fair is one of the top-ranking sourcing trips of serious buyers," said Jime Essink, president and chief executive of event organizer United Business Media Asia, according to the M&C news site.

According to organisers, there will be an increased police presence at this year's event - past jewellery fairs have been targeted by thefts.

More than 1,000 jewel thieves from South America arrived for the show in 2006.