The federal government has threatened to block a shipment of 65,000 live sheep bound for the Middle East on Tuesday if tough conditions fall short as video footage raises “serious concern”.

Whistleblower footage yet to be made public is expected to show that 2400 of almost 64,000 sheep died on a voyage from Fremantle, WA to the Middle East in August last year.

It is believed the video shows the sheep dying from heat stress, a lack of food and water, a significant build-up of animal waste and carcasses thrown overboard.

In a letter to the live sheep exporter on Friday, the Department of Agriculture and Water Resources said sheep bound for Kuwait, United Arab Emirates and Oman would not be transported without departmental approval.

Conditions stipulated in the letter included the ship’s consignment be reduced by 15 per cent, extra ventilation in the ship and an independent observer on board to file photos and video back to base daily, Fairfax reported.

The agriculture department said footage taken on the Emanuel Exports ship, in which reportedly 2400 sheep died from heat stress and other poor conditions in August last year, had raised “serious concern”.

An investigation is now underway with the department considering a revised heat management plan for sheep exported to the Middle East during the hottest months of the year, between July and August.

The whistleblower footage, provided by activist organisation Animals Australia, has yet to be made public with Channel Nine program 60 Minutes due to air the video images on Sunday.

Never before have we seen what really goes on inside live, long-haul exports – until now. 7.00 SUNDAY | Secret video recordings that will shock the world. #60Mins expose the shameful treatment of Australian animals on the high sea. pic.twitter.com/taziPKa96a

— 60 Minutes Australia (@60Mins) April 5, 2018

The New Daily sought comment from Animals Australia, who declined to comment on Friday, citing its arrangement with the whistleblower who provided the video footage and an exclusive media deal with the 60 Minutes program.

Emanuel Exports managing director Graham Daws said high mortality incidents like the Awassi Express voyage in August 2017 were “devastating” and was addressing issues from their own review and the agriculture department investigation.

“The viability of the live trade relies on the wellbeing of the animals in our care,” Mr Daws said in a statement.

“When animals welfare is not upheld, we jeopardise the food security of our overseas customers, the future of a significant long-standing market for producers and the support of the community.”

Federal Agriculture Minister David Littleproud said on Thursday he had been “shocked and gutted” after viewing the footage presented to him by Animals Australia.

“I’ve seen the footage and I was absolutely shocked and gutted,” Mr Littleproud said.

“This is the livelihoods of Australian farmers that are on that ship. That is their pride and joy and it’s just total bullshit that what I saw is taking place.”

The Australian Livestock Exports Council described the Animals Australia video footage “highly distressing and unacceptable” in a statement on Thursday.

“These deaths and the conditions in which they occurred are plainly unacceptable,” ALEC chief executive Simon Westaway said.

–with AAP