The ECB is to look into the influx of South African players in the English county game.

The bulk of those involved are playing by virtue of the Kolpak ruling, an EU loophole originally aimed at trade between the community and certain countries. The numbers have burgeoned since 2004, largely as a result of disenchantment at strict racial quotas in South Africa which have led to players looking to forge a career in England.

The match between Northamptonshire and Leicestershire which started today highlighted the issue, with each side fielding five South Africans. Leicestershire also included a West Indian Kolpaker and an Australian playing under a UK passport, while Northamptonshire had an Irishman.

David Smith, Leicestershire's chairman, has defended his county's position, explaining last week that the more experienced Kolpaks were being used to give his side backbone, enabling him to field up-and-coming English talent. But many have grown alarmed at the quantity of what are seen as cheap imports on county rosters.

"There is great concern about what is happening," an ECB source told the BBC. "The board will look at the situation of an almost doubling of non-English qualified players as a matter of urgency."

The ECB has tried to tackle the problem by imposing financial penalties. At present, if a county fields a Kolpak player they are deducted £1100 from their annual handout. But many counties have not been dissuaded by that and the numbers have continued to increase.

At present, Kolpaks are limited to a few Caribbean countries, South Africa and Zimbabwe, but it is believed that there is a possibility that Australia and New Zealand could be included in the near future, opening the floodgates to even more Kolpak players.

The ECB is unable under EU legislation to ban or impose limits on Kolpak players, although there are suggestions that the law could be reviewed as it was originally intended to apply to trade rather than labour.