King Harald V, who turned 75 on Saturday, was joined by his wife, Queen Sonja, as the Norwegian vocals of the touring Kori I choir echoed through the atrium of the Yarralumla hotel.

Norwegian flags were raised on Commonwealth Avenue on Sunday afternoon to mark the arrival of the king and queen on their first official trip to Australia.

The royal couple stood still while listening to the choir before smiling brightly when meeting a group of Norwegian children wearing traditional bunad costumes.

Norwegian media crowded around the couple as they leaned down to speak with Norwegian war veteran Olav Ottesen with children and their parents by his side.

Choir conductor Erland Dalen said it was a "fantastic honour" to perform before the king and queen, as their tour of Australia coincided with the state visit.

Members of the diplomatic community explained the king and queen were respected in Norway and popular among citizens.

On Monday morning, the king and queen will visit the Australian War Memorial for a wreath-laying ceremony and to sign the visitor's book before addressing the media.

In the afternoon, the royals will meet with the Governor-General, Sir Peter Cosgrove, and Lady Cosgrove at Government House before travelling to Parliament House to meet with Prime Minister Tony Abbott.

The couple will also visit Sydney and Perth in coming days and will be accompanied by a high-level delegation of business leaders and senior government officials.

Mr Abbott said Australia and Norway shared a war relationship and trade between the two nations was worth more than $1.2 billion in 2014.

"We both have strong oil, gas and mining sectors. Significant Norwegian companies have invested in Australia's energy, metals and agriculture sectors," he said.

"I look forward to meeting their majesties during their visit to Australia and welcome the growing strength of the ties between our nations."

More than 23,000 Australians have Norwegian ancestry.