The Australian prime minister took to Twitter to congratulate Mr Johnson, who was elected as leader of the party on Tuesday.

He will on Wednesday replace Theresa May as prime minister of the UK after winning the Tory leadership with 92,153 party member votes to 46,656 for his rival, incumbent foreign secretary Jeremy Hunt.

"Congratulations to Boris Johnson on his election as Leader of the Conservative Party in the UK," Mr Morrison posted on Tuesday night.

"I look forward to working with him and catching up at the G7 next month.

"He has a reputation for getting things done and making things happen. I wish him all the best as he charts the way forward for the UK. We have a great relationship with the UK and it will remain so with Boris."

Foreign Affairs Minister Marise Payne also congratulated Mr Johnson.

"I look forward to continuing our dynamic and enduring partnership with Great Britain," Ms Payne posted on Twitter.

"The democratic process we both cherish is founded in robust political competition. I applaud [?]Jeremy Hunt[?] for his campaign."

Ms May will leave office on Wednesday after seeing Queen Elizabeth at Buckingham Palace. Mr Johnson will subsequently be formally appointed by the Queen before he enters 10 Downing Street.

An ebullient Brexiteer and the face of the 2016 Brexit referendum's "Leave" campaign, Mr Johnson has promised to lead Britain out of the European Union on October 31 with or without a deal.

Australian Associated Press