New Zealand bio-security and food safety authorities moved proactively this morning to announce the discovery of a brain disease that affects sheep.

A high New Zealand dollar and reduced demand for sheep and beef looks set to hurt farmers in the coming year.

"Significant animal welfare issues" have been found among the 20,000 cows on the 22 farms owned by the Crafar family, a MAF inquiry says.

NZ's largest family owned dairy business is put into receivership by its banks Westpac, Rabobank and PGG Wrightson Finance.

New Zealand's largest family owned dairy business, Crafar Farms, has been put into receivership, Korda Mentha said in a statement.

Receivers were getting mud on their gumboots yesterday as they came to grips with problems of Crafar Farms.

Inspectors have begun urgent checks on the welfare of livestock at farms owned by the Crafar family, amid concerns that publicity over alleged cruelty could harm New Zealand's reputation.

Agriculture Minister David Carter says 'dirty dairy farmer' Allan Crafar could do huge damage to New Zealand's reputation.

Fonterra says it won't hesitate to take action, "including refusal to collect milk" if deliberate animal mistreatment is proven.

New Zealand's biggest privately held dairying operation allowed dozens of calves to slowly dehydrate to death.

Test results due back today may point scientists towards the cause of the mystery illness or illnesses affecting dogs and wildlife in the Hauraki Gulf.

Researchers believe they may be dealing with two or even three unrelated causes of illness in the Hauraki Gulf.

Health authorities have issued an alert for all eastern Auckland and Hauraki Gulf beaches after two dogs died and others fell sick.