A former leading voice of Queensland racing Larry Pratt has died in hospital aged 78.

AAP reports that Pratt, the younger brother of former premiership winning trainer Alby Pratt, had been in hospital for the past month after heart surgery.

His son Michael Pratt said Larry had been thought to be improving, but had a bad turn on Friday night.

"Right to the end he kept a close interest in racing," Michael Pratt said.

Pratt was the ABC's Queensland racecaller from 1964 to 1991, when the commission dropped race calls.

He was well known throughout Queensland and Australia for his accurate calls.

For 30 years he also worked as a turf journalist on the Brisbane Telegraph and Courier-Mail newspapers.

Pratt was a renowned tipster, as evidenced with his effort in tipping Spedito's Stradbroke-Doomben 10,000 double in 1975. Spedito started 20-1 and 25-1.

In recent years he has lived on the Gold Coast with his wife Val, who survives him along with their four children Michael, Kerri-Ann, Colleen and Tim and their children.