An Australian soldier has been killed and five others wounded in two incidents in Afghanistan.
The dead soldier, Sergeant Brett Wood, 32, is the 24th Australian to die in action in Afghanistan since 2001. Another 174 now have been wounded in action.
Defence force chief Angus Houston said the soldiers' families had been informed of the death.
"He was a magnificent soldier," Air Chief Marshal Houston said of Sgt Wood.
Defence Minister Stephen Smith said it was a very sad day for the nation and a tragedy for the family of Sgt Wood.
It would also be a "terrible reminder" for the families of the other 23 soldiers who have died in Afghanistan.
Sgt Wood and two other commandos were on clearance operations in southern Afghanistan when an improvised explosive device (IED) detonated on Monday.
The sergeant was killed, a second soldier suffered life-threatening wounds while the third suffered serious wounds.
Both wounded soldiers were evacuated by helicopter and are being treated at a medical facility, where they have been listed as seriously ill.
In a separate clash with insurgents, three Australian soldiers were wounded in a firefight on Monday.
They are receiving treatment at a medical facility and are expected to be in out-patients later on Tuesday.
Air Chief Marshal Houston said that the families of the wounded soldiers had been notified of their condition.
It was Sgt Wood's third deployment to Afghanistan. He also had served in Iraq, East Timor and Bouganville.
"He was also a decorated warrior," Air Chief Marshal Houston said, citing the sergeant's Medal for Gallantry awarded to him in 2006 after leading a commando team in extremely hazardous circumstances in Afghanistan's Chora Valley.
In 2007, Sgt Wood was again recognised for his service as the emergency action commander in the tactical assault group.
"I am told that Brad was highly professional, dedicated and an exceptionally nice guy," Air Chief Marshal Houston said.
"Brad's loss will be deeply felt across Australia's special forces community as he was an inspirational leader and a popular and highly-respected member of his unit."
Air Chief Marshal Houston offered his condolences to Sgt Wood's wife and said defence would take care of her.
"To the families of those wounded, I want them to know their loved ones are receiving the best possible treatment and will continue to act in their best interests as they recover."
Further details would not be immediately released because "operations are ongoing".