The Government has received a second warning that it may face an action in the European courts over the policy of charging a €20 fee for third-party submissions on planning applications.
However, the Government has said it has no plans to drop the fee, which was introduced to deter nuisance objections.
The European Commission has already sent a written warning to the Government saying it believed the planning fee contravened European environmental impact assessment regulations.
Yesterday, the Commission also sent a "reasoned opinion" to the Government, saying the fee also contravened a directive on industrial accidents.
Under the directive, the public has a right to be consulted on proposed large-scale industrial installations.
The Commission said it believed that the planning fee limited this right.
A reasoned opinion is the first stage in a process through which the European Commission takes a member-state to the European Court of Justice over the infringement of European directives.
The planning fee was introduced by the Government in a bid to deter nuisance objections.
Both private companies and public bodies had complained that necessary infrastructure and developments were being delayed due to objections from individuals who did not reside in the area.
Environmental and preservation groups have complained to the European Commission that the fee limits the ability of concerned citizens to object to developments which they believe would damage the natural and built environment.
A spokesman for the Department of the Environment maintained that the fee did not contravene European law, and that the Government had no plans to drop it, despite the latest warning.
"We have just received the reasoned opinion this afternoon and we will be studying it in conjunction with the Attorney General's office," he said. "However, we are satisfied that we are complying with European Union legislation."
Opposition MEPs, however, called on the Government to drop the charge immediately.
"The fee is in breach of EU legislation designed to prevent major industrial accidents," said Labour MEP Mr Proinsias De Rossa. This second challenge was a "further nail in its coffin", and "should be abolished immediately", he said.