The withdrawal of Australian combat troops from Afghanistan has finally been completed on Sunday. For the families of the Australian soldiers, it was indeed a reason to celebrate their being home this Christmas 2013.

"They are in the air, on the way home,'' David Johnston, Australian Defence Minister, said at a press conference in Sydney. The last batch left Oruzgan on Sunday.

Britain's Prince William (L) presents operational service medals for deployment in Afghanistan to soldiers of No 2 Company, 1st Battalion Irish Guards, during a ceremony at their barracks in Aldershot, southern England December 6, 2013. REUTERS/Carl Court/pool

A total of 25,000 Australian troops were deployed in Afghanistan following the Sept 11, 2001 attacks on the World Trade Centre in New York and the Pentagon in Washington. Of that number, 40 soldiers were killed and 261 seriously injured.

"We know they have paid a high price but that sacrifice has not been in vain,'' Prime Minister Tony Abbott said.

"Oruzgan today is a very significantly different better place than it was a decade ago."

"I want to say a very deep thank you to all of our servicemen and women.''

Australia will leave behind its Camp Holland base near Tarin Kowt, the troops' home since 2005.

Brendan Johnson, Camp Holland works manager Warrant Officer, told Herald Sun that while they are more than glad to come home to the waiting arms of their families, he strongly believed the local Afghan troops they will be leaving behind might find a hard time managing the infrastructure.

"It will be very hard for the Afghans to take over at the technical level,'' Mr Johnson said, noting the locals have limited knowledge of trades such as plumbing and electrical.

"They will go downhill but it will be livable. Hopefully.''

Among the infrastructure the Australian troops managed to build over the years and will be left behind include armoured accommodation containers, Green Beans coffee shop, a gym, sewage and power systems, a number of buildings and an airstrip.

Those are worth millions of dollars, Mr Johnson said.

Starting 2014, only 400 Australian combat troops will remain in Afghanistan. They will be there mainly to train and advise Afghan security forces, Mr Johnston said.