NATO chief thanks Aust in memorial visit

Many Europeans are unaware of Australia's costly role in the two world wars, NATO Secretary General Jens Stoltenberg says.

Mr Stoltenberg laid a wreath in the Hall of Memory at the Australian War Memorial in Canberra on Thursday and reviewed the Roll of Honour before signing the memorial's visitor book.

The NATO boss and former Norwegian prime minister has been visiting New Zealand and Australia for talks with political leaders and to emphasise three global security concerns - China and Russia's muscle-flexing, terrorism and cyber security.

"I am an example of the many Europeans that have not been fully aware of how much you contributed to our freedom, both in the First and the Second World War, and especially the First World War," Mr Stoltenberg said.

"It's extremely important that we express the gratitude to Australia.

"Because one thing is to participate in the Second and the First World War if you are already part of it or a European country, but you were actually sending people ... to the other side of the world and you suffered a lot to help us gain the freedom or maintain our freedom."

About 62,000 Australians died in World War I and 27,000 in World War II.