He said it was too late to do anything about the situation before October’s referendum, but said it should be looked at after the vote.
Mr Roche was responding to claims by former Irish European commissioner Peter Sutherland that RTÉ’s policy of giving equal airtime to the yes and no side contributed to the public’s confusion.
Mr Roche said: “There has been an extraordinary interpretation of Irish law and not specifically by the national broadcaster.”
He said Dáil members could not print even value-free literature giving ordinary information to voters on the Lisbon Treaty before the last referendum.
“This interpretation has come about because people have been very cautious and fear finding themselves back in the courts.
“This should be looked at in the future – post-Lisbon. There needs to be a national debate on the issue,” he said.
The Broadcasting Commission of Ireland has already said there was no requirement for broadcasters to give equal airtime for both sides of a referendum debate, but that coverage must be fair and balanced.
The Coughlan Supreme Court ruling said that both sides of a referendum debate should get equal time for party political broadcasts.
Mr Roche, in Brussels for a meeting of EU foreign ministers, warned that while polls indicated a general swing among the public in favour of the Lisbon Treaty, nothing could be taken for granted.
Ireland fully supported Iceland’s application for EU membership, which was discussed by the foreign ministers, Mr Roche said.
He believed issues peculiar to other member states should not be used as obstacles against membership.
The Dutch have linked their support for Iceland to that country compensating Dutch people who lost money in the Icelandic banks’ collapse.
Mr Roche believed that since Iceland was already a member of the European Free Trade Area and adopted much EU legislation, there should be no difficulty with its application.
Since it had a major interest in fishing, it would be likely to share Ireland’s views on fishing, he said.
If Ireland votes in favour of Lisbon, the legal guarantees on abortion, neutrality and taxation could be attached to the treaty on Iceland’s membership and this would turn them into protocols, he added.