Canberra: Australia will send an additional 200 troops to Afghanistan to work with Dutch-led reconstruction teams to help rebuild the war-torn nation, Prime Minister John Howard said on Tuesday.

Howard said the Australian Defence Force (ADF) personnel would be sent to Afghanistan in late July for a two-year mission, bringing the total number of Australian troops in the country to about 500.

"It will be part of a Netherlands-led provincial reconstruction team. The ADF contribution will be a mixed security and reconstruction task force," Howard told reporters.

Australia helped US forces oust the former Taliban regime in late 2001, then sent back 190 special forces troops last August for a 12-month tour of duty to counter growing rebel attacks.

The numbers were again bolstered last month with an extra 110 troops and two Chinook helicopters.

Defence Minister Brendan Nelson said the latest deployment of 200 Australian troops would operate in the southern province of Uruzgan, a former Taliban stronghold and opium poppy growing area.

"About half will be tradies [tradesmen] and engineers who will essentially be building roads and bridges and reconstructing local communities and the others will be logistics and light armoured protection," he said.

Howard said curtailing the area's thriving heroin trade would be a matter for local officials and not Australian forces.

The Netherlands said earlier this month that it would send an additional 1,200 troops to Afghanistan as it takes the lead role in Nato's 18,500-strong International Security Assistance Force (ISAF), which begins its two-year deployment in June. Nelson said his Dutch counterpart Henk Kamp would visit Australia next month to discuss details of the deployment.

Australian special forces in Uruzgan have already come under fire from militants and defence force head Air Chief Marshal Angus Houston last week warned of increasing suicide bombs attacks in Afghanistan.

"The level of activity has remained reasonably constant. What seems to have changed is the tactics that the anti-Afghanistan government elements are using," he told a Senate committee.

"In the past there was a tendency for them to use guerrilla marauding tactics almost exclusively. What we have seen in the last three months or so is the emergence of terrorist suicide bomber type tactics. That is a new development within Afghanistan."

Labor Party opposition spokesman Robert McClelland welcomed the mission to Uruzgan as a "valuable and strategically shrewd contribution to the fight against terrorism".

A staunch US ally, Australia also maintains about 1,320 troops in and around Iraq, including around 460 soldiers guarding Japanese reconstruction teams in the southern province of Al Muthanna.

Howard said he was confident that the new deployment would not over stretch the capacity of Australia's defence forces.

"We are confident that, based on the advice that we have received, that it can be carried out without imposing an unreasonable or unfair strain on the [military]," Howard said.