European milk farmers have dumped three million litres of fresh milk onto pastures and roads in a massive, organized protest against lowered dairy prices.

In Belgium, farmers spread milk across roads near the southern town of Ciney. Elsewhere, about 300 tractors dragged milk containers through plowed fields in southern Belgium, dumping a day's worth of milk production in that region.

Farmers spray milk on a field in Ciney, Belgium, on Wednesday, to protest slumping dairy prices. (Virginia Mayo/Associated Press)

"It is a scandal to dump this, but we have to realize what the situation is," said Belgian farm leader Erwin Schoepges. "We need a farm revolt."

Milk farmers say world prices have gone so low that they had to sell at half the production cost, leaving more farmers unable to pay their bills.

Prices have fallen 40 per cent since the spring, and European dairy farms are set to lose the equivalent of $14 billion this year unless the situation is remedied.

On Tuesday, farmers closed Belgian border crossings to the Netherlands and to Germany to push demands for higher prices.

Most EU nations want to shore up milk prices but they disagree on how to do that. The EU head office opposes a lowering of quotas, but the quotas are scheduled to end in 2015.

Since the recovery from the Second World War, agriculture is one of the most shielded sectors of the European economy, as governments have sought to end hunger and rationing by paying farmers to increase food production.

But despite decades of being largely exempt from free market forces, farmers have not been protected by governments from the global financial crisis that caused demand to crash.

With files from The Associated Press