CANBERRA, Dec. 20 (Xinhua) -- Prime Minister Scott Morrison has thanked Australian troops for their service during a secret end-of-year trip to the Middle East.

Morrison met with 800 Australian Defence Force (ADF) personnel in Iraq during the trip, which came ahead of Christmas.

Of the 800 troops, 300 are members of Task Force Taji, a mission that has trained 40,000 Iraqi troops to fight Islamic State (IS) since 2015.

"I understand it's a sacrifice and I understand it's a big thing to be away from your family at this time of year and that's why I've decided to come just to say thank you from one Australian to another," the Australian prime minister told the servicemen and women at the Taji Military Complex near Baghdad.

"On behalf of my family, to you and your families, I want to say thank you very much for your service," Morrison said.

"But I also want to thank you as a prime minister, as the leader of the government, as a member of the Australian parliament, on behalf of our entire nation."

The ADF has been engaged in the fight against IS in the Middle East since August 2014.

Australia will spend 180 million Australian dollars (128 million U.S. dollars) on aid for Iraq between 2014 and 2020.