SYDNEY, AAP – BHP has blamed Western Australia’s tough border controls for a shortage of train drivers which contributed to producing less iron ore in its first quarter.

The miner on Tuesday revealed production of its most lucrative commodity fell three per cent from the previous quarter, and four per cent on the 2020 first-quarter.

COVID-19 border restrictions led to a shortage of train drivers, who transport materials to ports. Much of the iron ore goes to steelmakers in China.

BHP said the worker shortage had improved in September.

Iron ore production was also affected by planned maintenance work in WA.

Maintenance work also meant the miner produced less nickel (down 20 per cent on same quarter last year), metallurgical coal (down nine per cent) and copper (down nine per cent).

Production of energy coal was up 17 per cent, while petroleum output improved by three per cent.

Chief executive Mike Henry said production had been reliable while completing major maintenance works.

Full-year production forecasts for all materials remain unchanged.

Shares on the ASX were down 1.53 per cent to $38.59 at 1136 AEDT.