Tributes have flowed for long-serving officer Graeme Donnelly, 52, who died of a heart attack while riding around Lake Illawarra last Friday.

Friend and cycling companion Wally Erven said Insp Donnelly loved cycling because it allowed him to de-stress.

"Being in the police force, it gave him a separation," he said.

Insp Donnelly was the father of junior Australian cycling champion Aaron Donnelly - and Mr Erven said the apple hadn't fallen far from the tree.

"Aaron's not a professional cyclist for no reason - it's in his genes and he got that from his father."

Wollongong acting superintendent Tim Beattie said the policing community had been shocked to learn of Insp Donnelly's death.

Insp Donnelly spent his career based in Wollongong until about 12 months ago when he transferred to Sydney and was attached to a specialist police unit.

"Graeme was a highly respected member of the police force who performed a significant amount of his service in the Illawarra area," Supt Beattie said. "He is regarded by all those who knew him as being a good bloke."

A tribute has also been posted on the Cycling NSW website.

"His loss is greatly felt by the Illawarra Cycle Club and the NSW cycling community," the statement read.

Insp Donnelly's funeral will be held at Wollongong Catholic Cathedral, 36 Harbour Street, at 1pm on Monday.