Media reports on Tuesday claimed BHP Billiton and Rio Tinto had notified Japanese steel makers of their intention to increase prices for the bulk commodity for the three months to September by 22 per cent to 23 per cent.

The hike would see iron ore priced at about $US147 a tone, the reports claimed.

The 40-year-old annual iron ore pricing system collapsed in April when Rio Tinto followed BHP Billiton and Brazil's Vale in adopting quarterly negotiated contracts.

A BHP Billiton spokeswoman said the company did not comment on iron ore price negotiations.

Rio Tinto was not immediately available for comment.

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