The number of South African and West Indian players who are allowed to play in county cricket could be reduced after the European Commission (EC) changed its interpretation of a key employment law.

The EC has altered its stance in the Cotonou Agreement which allows players from the European Community and many African, Pacific and Caribbean countries to play in England as domestic players. They have become known as Kolpak players after the former Czech handball player Maros Kolpak, who won a ruling in the European Court of Justice in 2004 allowing him to play professionally in Germany without being classed as a foreigner.

South Africans such as Lance Klusener, Andrew Hall, Nicky Boje, Jacques Rudolph and Francois du Plessis and West Indians Pedro Collins and Omari Banks have played in England as domestic players, but the law will now be read in a way that could restrict their freedom of movement.

"The ECB have noted the recent developments and are looking at the possible implications of that," a spokesman said.

The new ruling could would not affect Kolpak players who are under contract, but any future signings would be regarded as overseas.