The prime minister met with Canadian prime minister Justin Trudeau on Sunday, before holding a lunch with Australia’s community champions at Australia House in London.

Albanese met with the new king along with his counterparts from the 14 Commonwealth realms.

He revealed key details for the memorial service in Australia for the late Queen, to be held on Thursday.

Australians will get a one-off public holiday for the national day of mourning.

Albanese said Australian Idol star Anthony Callea will perform at the event, to be held at Parliament House in Canberra, with TV presenter Melissa Doyle to host.

“It will be an important day to pay tribute to the life and service of Queen Elizabeth II,” Albanese said.

All state and territory leaders, as well as justices of the High Court, will attend the service.

Albanese said he and Opposition Leader Peter Dutton will give “short tributes” to the late monarch.

The prime minister also met with British prime minister Liz Truss in Kent on Saturday, where they spoke about national security in the Indo-Pacific.

Earlier in the day, Albanese was forced to dismiss questions about changes to the constitution following the Queen’s death, saying the timing was not appropriate.

“I don’t think now’s the time to discuss those issues, and I have made that clear,” he said.

“This is a time in which we should acknowledge the life of service of Her Majesty Queen Elizabeth.”

He said the late monarch had a “close affinity” to Australia, always standing with its people at “times of difficulty”.

Albanese said there was a standing invitation for King Charles to visit Australia, adding that he would be comfortable with the monarch continuing to express views on issues such as climate change.

“If he chose to do so, then of course that would be a matter for him. But I think that should be respected if he does choose to do so,” he said.

The Queen’s funeral will take place on Monday at 7.30pm, Adelaide time.

King Charles thanked people from Britain and across the world for their messages of sympathy.

“Over the last 10 days, my wife and I have been so deeply touched by the many messages of condolence and support we have received from this country and across the world,” Charles, who has toured the United Kingdom since his mother’s death, said in a statement on Sunday.

Camilla, the queen consort, paid tribute to her mother-in-law in a video message, saying the monarch “carved her own role” as a “solitary woman” on a world stage dominated by men.

“I will always remember her smile. That smile is unforgettable,” Camilla said.

Monday has been declared a public holiday in Britain, and the funeral will be broadcast to a huge television audience worldwide and screened to crowds in parks and public spaces across the country.

Police officers will be on duty as part of the biggest one-day policing operation in London’s history.

Crowds also gathered Sunday near Windsor Castle, where the queen will be laid to rest at a private family ceremony on Monday evening.

Ukraine’s first lady, Olena Zelenska, was also among mourners paying respects to the queen’s coffin.

British royal officials said Zelenska met with Catherine, the Princess of Wales, at Buckingham Palace on Sunday afternoon.

They did not release further details.

The lying-in-state continues until early Monday morning, when the queen’s coffin will be moved on a gun carriage pulled by 142 Royal Navy sailors to nearby Westminster Abbey for the funeral, the finale of 10 days of national mourning for Britain’s longest-reigning monarch.

After the service at the abbey, the late queen’s coffin will be transported through the historic heart of London on the state gun carriage.

It will then be taken in a hearse to Windsor, where the queen will be interred alongside her late husband, Prince Philip, who died last year at 99.

-AAP