Munich  - German dairy farmers began Tuesday a national protest strike, refusing to supply milk to dairy factories until they are offered a higher price for their produce.

Romuald Schaber, leader of the BDM German association of 30,000 dairy-cattle farmers, said the group expected the boycott to last between a week and 10 days.

He asserted that participation was "overwhelming" with 80 per cent of farmers taking part "in some regions."

The unsold milk is being fed to calves or dumped in farm-waste tanks.

The farmers are angry at EU plans to increase output quotas and depress the market price of milk in the European Union. Brussels says it must respond to growing global demand for milk, especially from booming Asian nations.

The BDM maintains that a farm gate price of less than 40 euro cents (63 dollar cents) per litre for milk is uneconomic.

The dairy factories of Germany are controlled by a few powerful companies which currently pay 27 cents a litre in north Germany and 35 cents a litre in south Germany for milk, according to BDM data. (dpa)