Tim Fischer was in "remarkably good spirits" until the very end of his decade-long battle with cancer.
National Party stalwart Larry Anthony last saw the former deputy prime minister about a week before he died.
"He was in remarkably good spirits, always interested in other people, we reminisced about the past," Mr Anthony told ABC radio on Friday.
"He seemed to be at peace."
Mr Fischer died at the Albury-Wodonga Cancer Centre on Thursday, surrounded by close family members.
Mr Anthony reflected on visiting Mr Fischer when he was ambassador to the Holy See.
His service was also recognised by Pope Benedict, who made him a papal knight in 2012.
"I don't think we'll see the likes of a Tim Fischer ever again," Mr Anthony said.
Acting opposition leader Richard Marles remembered Mr Fischer as a gifted diplomat.
"His ability to project his warmth and generosity of spirit across such a diverse range of cultures, was extraordinary," he told Nine's Today program.
The 73-year-old had been fighting acute leukemia for the past 10 months, and cancer more generally for the past decade.
Despite knowing stricter gun controls would be hard for Nationals members and regional people to accept, Mr Fischer was crucial to delivering the laws after the Port Arthur massacre in 1996.
Home Affairs Minister Peter Dutton credited the gun laws for preventing deaths in attempted terrorist attacks in Australia.
"He's a figure that was likeable, he was serious on the policy front, he obviously represented our country very proudly," Mr Dutton said.
Prime Minister Scott Morrison has offered Mr Fischer's family - wife Judy and sons Harrison and Dominic - a state funeral to honour him.
Former prime minister John Howard described Mr Fischer, with whom he formed a close governing partnership after the coalition's election win in 1996, as an authentic Australian with an endearing quirkiness.
"People recognised him for being someone who served his country ... and he dedicated his life to politics," Mr Howard said.
"He was able to identify the broader national picture, even on issues that mightn't immediately be appealing to his own constituency."
When he retired from politics, Mr Fischer worked tirelessly for many causes, including autism, veterans affairs and agricultural research.
He has been praised by many of those groups he supported, including farmers, rural doctors and Autism Spectrum Australia.
A condolence book will be opened on Monday at the Howard Library in Old Parliament House in Canberra.
Australian Associated Press