The British government is facing heavy fines from the European Union if it fails to prove it is cracking down on illegal dumping in Northern Ireland.
Every year hundreds of thousands of tonnes of illegal waste, much of it from the Republic, is illegally dumped across the border.
In the past two years, 60 illegal dumps have been discovered in Northern Ireland, many of them in border areas.
Environmental campaigners believe thousands of tonnes of rubbish are being left in the countryside, seriously polluting ecosystems and waterways and endangering human health.
The European Commission has now given the British government two months to respond to allegations it has failed to prevent some dumps in the North from handling waste which could harm the environment.
It is also accused of failing to close down sites acting in contravention of their waste disposal licences or without any licence at all.
If the response does not satisfy EU officials, heavy fines could be imposed.
The Department of the Environment in Belfast says a dedicated crime team has been established to enforce legislation and crack down on the illegal transportation of waste from the Republic.
