Australia is considering sending more troops to Afghanistan as the security situation there deteriorates, Defense Minister Brendan Nelson said Sunday.

Nelson said a 240-strong reconstruction team being deployed this month in the country's troubled south would likely require greater protection because of the worsening insurgency.

"The threat level and the risks in Afghanistan have been increasing substantially over the last few months," Nelson told commercial television.

"I've been watching it very closely, I'm very concerned about it, and in fact I have been discussing with the leadership of the Australian defence force the nature and the size of our deployment to Afghanistan."

Some 190 Australian special forces were deployed to Afghanistan last year to counter growing rebel attacks.

A further 240 troops are due in the country this month to work on a Dutch-led reconstruction project in troubled Uruzgan province.

Half of the new taskforce will be tradespeople and engineers, with the remainder an infantry protection unit.

Nelson said it was likely the size of the protection contingent would increase.

"I think there is an argument for us increasing the close ground force protection of our reconstruction taskforce," he added.

The insurgency waged by militants from the ousted Taliban regime and their supporters is gaining momentum in Afghanistan, with rebels taking on coalition forces in full frontal battles and guerrilla-style bombings.