Former NSW government minister and well-known racehorse owner/breeder Paul Whelan has died aged 75 after a long illness.

Whelan was a member of the NSW parliament from 1976 to 2003 and a minister in the Neville Wran and Bob Carr-led governments.

When he retired from politics, Whelan devoted himself to thoroughbred breeding and racing as the proprietor of Luskin Park Stud in the Hunter Valley.

"Paul was a visionary and was admired by all," Racing NSW chief executive Peter V'landys said.

"He was respectful to anyone he met, on any level, and always had a smile on his face.

"Paul will be missed by everyone in the racing industry that had the pleasure of his acquaintance and we would like to pass on our sincere condolences to his family."

Whelan was born and raised in the Sydney suburb of Ashbury.

He was admitted as a solicitor in 1968 and barrister in 1988, then became an alderman on Ashfield Municipal Council from 1970 and was Mayor from 1971 to 1976.

He held several portfolios in the NSW government and was state's longest serving police minister from 1995 to 2001.

After retiring from politics, Whelan went into thoroughbred breeding and racing, and was proprietor of Luskin Park Stud in the NSW Hunter Valley.

He bred some top-flight performers including Foxwedge and Rock Classic, and also part-owned Group One winner Flying Artie with his long-time friend, Wilf Mula.

"Paul was a great man and above all, a caring human being," Mula said.

"We went to school together and once he got out of politics, Paul went into breeding racehorses which was his passion.

"Paul was an outstanding person and will be missed by many."

Whelan is survived by wife Colleen and his extended family.