Treasurer Joe Hockey is preparing voters for another tough budget, warning tax revenue could continue to be pummelled by falling iron ore prices.

In an interview with the Australian Financial Review, Mr Hockey said the price of iron ore could fall to as low as $35 a tonne, down from $120 a year ago.

Iron ore is already just $47 a tonne, and Mr Hockey said “there seems to be no floor”.

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Mr Hockey’s prediction comes as iron ore giants Rio Tinto and BHP Billiton continue high levels of production despite falling prices, thus contributing to the supply glut and further pushing down prices.

Mr Hockey told the AFR that this falling tax revenue from mining profits, combined with the lack of pick-up in other parts of the economy, means the government must remain committed to cutting services in the May budget.

In this hard line, he compared himself to NSW premier Mike Baird, who stuck to his policy of selling the states electricity networks despite its unpopularity.

“We’re not afraid. We’re more of a Baird mould than the [former Victorian premier] Napthine mould,” he said.

“The moment you walk away from structural savings is the moment you concede you’re never going to get back to surplus.”

The Treasurer’s comments come as a Fairfax-Ipsos poll puts his personal approval rating on a par with Tony Abbott at minus 25.

The poll also showed that voters still overwhelmingly oppose one potential budget-saving measure: a rise in the GST. However, the good news for Mr Hockey is that support for a GST hike has increased by seven percentage points to 37 per cent.