Analysts expect Rio Tinto and BHP Billiton to post weaker production results for the March quarter after a spate of cyclones disrupted operations in WA and QLD.
In a research note UBS said it expected BHP's iron ore shipments to drop two per cent for the quarter to 39.5 million tonnes.
Analysts also tipped a two per cent drop in sales from the company's QLD coal operations on the back of weaker port export statistics.
“The March quarter is typically a weaker quarter driven by seasonal weather events and scheduled maintenance,” UBS said.
Along with BHP, UBS said Rio Tinto would also be hurt by poor weather over the quarter, with analysts tipping a seven per cent fall in iron ore production to 58.2mt.
Rio Tinto is expected to release its March quarter production report today, and BHP is scheduled to report on Wednesday.