Anthony Albanese will meet King Charles III during his stay in London, cementing Australia's importance to the new monarch.
The prime minister, Governor-General David Hurley and their partners have arrived in the British capital for a series of events commemorating the late Queen Elizabeth II.
Soon after touching down, Mr Albanese and partner Jodie Haydon laid a floral tribute, a small bouquet of white flowers, at Green Park in Westminster.
"It's a great honour to be representing Australia here," he said.
"Quite clearly, what we can see all around us is the affection in which Her Majesty Queen Elizabeth was held by people here in the United Kingdom but also of course in Australia and right around the Commonwealth."
Mr Albanese said his visit was about "commemorating a life well-lived".
He will view the Queen's coffin in Westminster Hall and sign the official condolence book at Lancaster House before a brief audience with King Charles at Buckingham Palace.
The King will also host the prime minister, heads of state and international VIPs at an official function over the weekend.
Australian Monarchist League chairman Philip Benwell said Charles has always kept a special place in his heart for Australia, particularly after spending time in regional Victoria in the 1970s.
"King Charles has committed himself to following in the footsteps of his late mother and to likewise dedicate himself to the service of his people," he told AAP.
"He will always make time to meet with his Australian prime minister, and the gathering for the funeral of the late Queen offers an opportunity for this."
Mr Albanese will also meet with new UK prime minister Liz Truss.
Downing Street has framed the conversation as a chat rather than formal bilateral talks.
It says the get together, at Chevening rather than the prime minister's official country residence Chequers, will be an opportunity for condolences over the Queen's death, with politics likely to come up.
While there has been no word from Mr Albanese's office on the nature of the discussions with Ms Truss, trade arrangements are the most likely topic
Ms Truss will also meet on Saturday with New Zealand PM Jacinda Ardern, while Mr Albanese is scheduled to have talks with his Canadian counterpart Justin Trudeau.
The Queen's funeral will be televised at 8pm AEST on Monday.
- with reporting from PA
