Australia's high commission in Pakistan has been targeted in a suspected poisoned letter attack against Western embassies in Islamabad.

The Foreign Affairs Department confirmed Australia's diplomats in the country yesterday received a ''malicious and threatening letter'' containing a packet with an unknown powder.

''It appears that other embassies in Islamabad also received similar letters,'' a spokeswoman said.

''The response by our high commission was quick and effective. No one suffered any ill effects from this incident. Our posts overseas are well equipped to deal with mail incidents, as shown in this case.''

According to AFP reports, the powder was sent with letters claiming it was a sample of ''poison'' that would be hidden in NATO supplies should Pakistan lift a blockade on convoys for troops fighting the Taliban in neighbouring Afghanistan.

The border has been closed to NATO convoys supplying the war effort in Afghanistan since November after a US air strike killed 24 Pakistani soldiers at a border post.

Representatives from France and Britain have also reportedly been targeted.