The West Australian government's bid to take legal action against a Perth-based livestock exporter is being hamstrung by the Commonwealth, the state's agriculture minister says.
Alannah MacTiernan supports the federal government commencing its own criminal investigation into Emanuel Exports' Awassi Express journey on which thousands of sheep died of heat stress, labelling it "a long overdue exercise of responsibility".
But it is refusing to cooperate with WA's separate legal bid.
Ms MacTiernan told AAP she had been asking for export licence documents for months but "commercial confidentiality" reasons were being cited, which was not acceptable.
"They should be cooperating," she said.
"If they are truly serious (about improving animal welfare standards), they would be helping us."
The minister also said her federal counterpart David Littleproud believed he had resolved the Awassi controversy by reducing stocking densities following the review he ordered into the Middle Eastern summer trade by industry vet Michael McCarthy.
But Mr Littleproud had not gone far enough to address high humidity in Qatar, which is most intense in July and the first half of September, Ms MacTiernan said.
"He has promised a lot and not delivered."
She asked live exporters to voluntarily hold off sending ships to Qatar during that peak humidity period, and said Mr Littleproud should have adopted Dr McCarthy's heat stress model.
"Mortality is not the proper yardstick of acceptability. It is the distress caused to the animals even if they do survive,' she said.
Emanuel Exports declined to comment.
