Mr Cowper said the racing, pacing and chasing industries represented one of the biggest employers in his electorate and none of them supported the concept of a TAB sale.
"None of the owners, drivers or trainers racing at Pinjarra on August 17 are supporters of the TAB sale plan because they know first-hand how the TAB is the mainstay of the WA industry and have seen the highly damaging impacts of TAB privatisation on their counterparts in other States," he said.
Mr Cowper said there had been a great deal of public speculation on a TAB sale but as yet there was no detail with the proposal.
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READ NOW"You don't discuss the sale of an asset without knowing what you will get for it, or what detrimental impact a sale might have.
"Former Premier David Brand set up WA's TAB in the 1960s to"sanitise" an industry that had become dominated by a core of wealthy off-course bookmakers.
"Our TAB has become the envy of the other states and they have been urging us not to allow the TAB to be privatised," Mr Cowper said.
"We are hoping for a strong showing of anti-TAB sale supporters at the Pinjarra meeting."
He said it would also provide an ideal opportunity for those who had not yet experienced the impressive facilities now provided at Pinjarra to make up a party and enjoy the thrills and high standard of pacing now available.