Mr Kobelke entered state parliament in 1989 and served as a minister under premiers Geoff Gallop and Alan Carpenter before retiring in 2013.

Premier Mark McGowan said he was deeply saddened by Mr Kobelke's death, having served with him for 20 years.

"He was a terrific person, genuinely committed to WA and a formidable minister, who was respected across the political divide," Mr McGowan tweeted.

Senior Labor minister Sue Ellery described Mr Kobelke as a hard-working Labor stalwart and thoroughly decent man.

"(He was) always willing to help a new MP, including this one," she said.

Australian Associated Press