Four suspected cases of foot-and-mouth disease have been detected in Holland.
Preliminary results on four cows have shown signs of the disease, the agriculture ministry said.
More tests are being done and the final results will be available on Friday.
The ministry said four companies that had handled the animals were under observation and the area around them was closed for a six-mile radius.
About 300 cattle and four goats are to be destroyed on Wednesday as a precautionary measure.
The animals were on a farm in the eastern part of the country in the province of Gelderland.
On Monday the government lifted six-day-old restrictions on transporting cloven-hoofed animals to slaughterhouses, except in a small area of Gelderland.
The ministry said there was no immediate plan to reimpose the restrictions.
Dutch farmers already have destroyed thousands of cattle, sheep, goats and deer imported from Britain and France after the disease was discovered in those countries.
Until today, there had been no serious symptoms detected in the Netherlands.
More than 300 cases of foot-and-mouth disease have been confirmed in Britain, but only six cases have been detected on the Continent, all on a cattle farm in north-west France last week.
The French government says the disease has been contained.
The Dutch were hard hit by an international ban on buying livestock and meat products from Europe.
Dutch farmers sold more than (stg£6bn) worth of meat and animals in 1999.