CANBERRA is keen for Pakistan to complete its investigation into the "appalling" cull of 21,000 Australian sheep as soon as possible.

Agriculture Minister Joe Ludwig, in Bangkok assessing Australian food exports into South East Asia, also raised concerns about how Australian live sheep exporter Wellard, based in Fremantle, had managed to lose control of the shipment.

The sheep were landed at the Pakistan port of Karachi after being turned away from their original destination, Bahrain.

Then Pakistan livestock officials ordered the sheep be culled due to disease concerns.

The graphic footage of the cull was aired on Australian TV, provoking calls for an investigation and an end to live animal exports, worth millions of dollars to key markets in the Middle East and South Asia.

"It's important that they (Pakistan) have undertaken an investigation because we do want to get to know why that happened," Senator Ludwig said.

"It was an appalling circumstance; we want it addressed through that investigation," he said.

Prime Minister Julia Gillard held direct talks on the issue with her Pakistan counterpart, Raja Pervez Ashraf, during this week's Asia Europe Summit of leaders in Vientiane, Laos.

"I would leave it to the Pakistan government to finalise their investigations," he said.

"They need to finalise those as quickly as possible. The regulator in Australia will undertake their investigations and also finalise their report as soon as they can.

"I don't put timelines on these things - I don't expect them to be too long - but it's always impossible to say how long.

"The compliance framework we have in place is a tough one, and we'd expect the regulator to look very hard at what happened and what we can do to ensure that it doesn't happen again."

Senator Ludwig said it appeared Wellard had lost control of the shipment.

"It's important from our perspective that we look at the circumstances how Wellard lost control of the animals through that supply chain," he said.

"We do demand that animal welfare be put at the heart of the trade."

Senator Ludwig welcomed the voluntary suspension of trade while the investigations were ongoing, but said generally, the trade globally should continue.

"This is a good trade - 1.5 million exported over the last four months. There's many sheep out of Western Australia - it's important for the economy of WA; it's important for the jobs and opportunities in WA, particularly around sheep," he said.

"What is sometimes overlooked in all of this is the context.

"The majority of animals that are now exported are through the (exporter supply chain assurance system) ESCAS system," he said.

ESCAS was introduced to ensure animal welfare standards in overseas markets after graphic footage of Australian cattle being mistreated in Indonesia was also shown on Australian television last year.