The Defence Force has confirmed the death of an Australian commando during an incident in Afghanistan overnight.

Sergeant Brett Wood was a decorated soldier serving his third deployment to Afghanistan.

The 32-year-old from Victoria was killed and two other diggers were seriously wounded by an improvised explosive device during an operation in Uruzgan province.

The wounded men were evacuated and are being treated at an ISAF facility. Both are listed as seriously ill.

In a separate incident, three Australian soldiers were wounded in a gunfight with insurgents. They are being treated in Tarin Kowt and are expected to become outpatients later today.

Chief of Defence Air Chief Marshal Angus Houston made the announcement in Canberra this morning.

He says Sergeant Wood's wife and family have been notified.

"He was a magnificent soldier," Air Chief Marshal Houston said of Sergeant Wood, who also served tours in Bougainville, East Timor and Iraq.

He says the Sergeant was highly professional, dedicated and "an exceptionally nice guy".

"He was an inspirational leader and a highly respected and popular member of his unit.

"He was also a decorated warrior. In 2006 he was awarded the Medal for Gallantry for his bravery in action as commando team leader in extremely hazardous circumstances."

Air Chief Marshal Houston offered his "deepest condolences" to Sergeant Wood's wife.

"I want her to know that we are going to take care of her and support her as we bring Brett home, lay him to rest, and honour his outstanding service to our nation."

Sergeant Wood's death brings to 25 the total number of Australians killed while serving in Afghanistan - 24 with the Australian Defence Force and one with British armed forces.

Thirteen Australians have been killed in the past 12 months.

Serious injuries

Air Chief Marshal Houston says one of the men wounded in the IED blast suffered life-threatening injuries but that he and his comrade are listed as serious - one level below the worst injury rating of very serious.

He says the three men injured in a separate firefight suffered fragmentation injuries and are expected to be treated as out-patients later today.

He said all the wounded are receiving the best possible care. The badly wounded men may be evacuated to specialist facilities in Germany if such care is needed.

Air Chief Marshal Houston says further details of the incidents cannot be released at this time because operations are ongoing.

The Defence chief says the morale in Sergeant Wood's unit, 2 Commando Regiment, is still very high.

"They are a unit of warriors, and to a large extent they are the unit most involved in our operations in Afghanistan," he said.

"They are absolutely the best of the best."

Australian forces have been active in Afghanistan in various roles since the war's inception in 2001, with 1,550 personnel currently deployed.

A total of 174 Australian soldiers have been wounded.

Dedicated

Prime Minister Julia Gillard says her thoughts are with the families of Sergeant Wood and the wounded soldiers.

"Our hearts go out to his wife, who would be struggling to absorb this very dreadful news," Ms Gillard said.

"He was a young man who had dedicated his life to the defence of this nation. This is a very difficult day for the nation, but most particularly a very difficult day for his family."

Defence Minister Stephen Smith says Australia continues to be in Afghanistan for national security and national interest reasons.

Mr Smith says the nation has to steel itself for "further fatalities and casualties" as the spring and summer fighting season gets underway.

"Today we have another terrible blow for our nation, a tragedy for an Australian family.

"But we continue with resolve because we very strongly believe that we are seeking to stare down international terrorism, seeking to protect not just Australia's national interests, but the international community's."