Privatising WA's poles and wires utility Western Power would be a mistake that would cost the state $550 million a year and threaten electricity supply, says state Labor leader Mark McGowan.

The Labor opposition ramped up its campaign against the privatisation last week – holding media events every day, including launching a public petition and visiting at a transformer manufacturing business whose contract with Western Power had been axed, costing 80 jobs.

The Liberal National government’s Treasurer Mike Nahan wants to sell Western Power, Fremantle Port and the TAB betting agency and use a significant part of the proceeds to pay down debt.

Western Power’s $8 billion in debt represents about a quarter of government borrowings.

Mr McGowan says that as well as risking jumps in electricity prices and a fall in service quality – with the government denies will occur – the risk to supply was the most serious issue.

“Mr Nahan doesn’t look at these issues based upon facts, he looks at them based upon his ideology and his ideology is extreme privatisation, that’s what he wants to do to Western Power,” Mr McGowan told reporters on Sunday.

“I think my position is the conservative position, it’s the safe position – don’t sell off an asset that provides an essential service in a monopoly environment when you can’t connect into the other states’ electricity supplies and where the asset provides a huge revenue to taxpayers.”

The Barnett government fought back against Labor during the week, floating the idea of a 50 per cent-plus sale of Western Power in which it would be floated on the share market and both mum and dad investors and superannuation funds could separately buy shares.

Super funds were key players in the controversial $16 billion Ausgrid sale in NSW, which blocked a Chinese bid.