Treasurer Mike Nahan says WA will not agree to any changes to GST arrangements for online purchases overseas unless WA's dwindling share of the national tax take is reformed.
Dr Nahan acknowledged yesterday that he was using the issue as leverage, saying: "It's called playing the cards you're dealt with."
He said the issue was discussed at the most recent meeting of State and Federal treasurers.
"I made it quite clear we are interested in doing the research but we will not agree to any changes to the GST - including for online shopping - unless there is a rigorous, firm decision to alter the GST sharing arrangements," Dr Nahan said.
He said he and Treasury would continue to "keep an eye on" iron ore prices, which are languishing about $30 a tonne below Treasury's 2014-15 full-year forecast, potentially costing the State Budget billions of dollars.
"We're OK through the end of this financial year," he said.
"I will start worrying about it into next financial year some time. Iron ore prices are very difficult, they go up and down."