Former prime minister John Howard has weighed in on Opposition Leader Peter Dutton, describing him as bringing a "pragmatic set of principles".
Mr Howard publicly congratulated the new leader of the coalition for the first time on Thursday, while launching a book about his government at the National Press Club.
The former Liberal leader said he was proud of what Mr Dutton had achieved and noted for the first time in the coalition's history it was led by two Queenslanders - Mr Dutton and Nationals leader David Littleproud.
Mr Dutton held the roles of assistant treasurer and minister for workforce participation in the last three years of the Howard government.
"You brought into parliament a pragmatic set of principles and that those two words do fit together more naturally than many people seem," Mr Howard said.
"I found the work you did in the various portfolios I entrusted to you ... a capacity and a grit and a determination."
Mr Dutton said as the last former Howard government-era minister in parliament he felt like a "Japanese holdout".
He said it was an "indisputable conclusion" the Howard government flourished because it had "character, convictions, and courage".
Mr Dutton said the nation owed Mr Howard and late Nationals leader Tim Fischer a "great deal" for working together in the best interests of the country.
"Their example reminds all of us as leaders of the parties today, to ensure the coalition not only survives, but thrives as well," he said.
Mr Howard described himself as a "very passionate coalitionist".
The Art of Coalition is a book of essays edited by David W Lovell and Andrew Blyth, published by NewSouth, examining the relationship between the Liberal and National parties from 1996 to 2007.