Western Australia's Department of Environment said the animals died during the six weeks to the end of January after falling into and becoming trapped in a trench dug to house the pipeline.

Newcrest mining company, which is building the pipeline between Port Hedland and Telfer, has been ordered to work harder to protect the local fauna.

"The company is allowed a 60 kilometre (32 miles) trench at any one time to construct the pipeline, provided adherence to strict controls to minimise impacts on wildlife," the department's environmental management director Robert Atkins said.

"However, our surprise audit on February 10 and inspections by other government authorities have found the numbers of animals dying in the trench to be unacceptable."

Atkins said Newcrest was now required to put a new management plan in place which included daily monitoring of animal deaths and weekly reports to authorities.

TERRA.WIRE