TONY Abbott has urged the mining industry to "demonstrate their gratitude" to former resources minister Ian McFarlane in "his years of retirement".
Mr Abbott also admitted to once taking an envelope containing $5000 from a "well-known millionaire".
The former prime minister made the comments while paying tribute to retiring colleagues on Wednesday night in the House of Representatives.
Mr Abbott said Mr McFarlane's scrapping of the mining tax was a "magnificent achievement" and "I hope this sector will acknowledge and demonstrate their gratitude to him in his years of retirement from this place".
In speaking of Senator Bill Heffernan, who he described as the most honest MP he had met, the former PM recalled being a "relatively new member of parliament" when he received an invitation from a "well-known millionaire" to Christmas drinks.
"As I was leaving he gave me an envelope and said, 'That's your Christmas present.' When I opened it up, it contained $5000 in cash," Mr Abbott said.
"I can tell you, the Abbott family in those days could have used that money, but it did not feel right.
"I rang Bill Heffernan for his advice and he said: 'Once bought, always bought. Give it back and say to that person, 'Please write out a cheque for the campaign'.
"I have not always agreed with Bill Heffernan, but I have always admired him as the most honest and selfless member of parliament that I have ever met."