In Brussels, Michael Meacher, the environment minister, opposed calls by his French counterpart Dominique Voynet for a meeting to agree a freeze. Mr Meacher said that existing British controls were adequate, including a voluntary ban on large-scale commercial plantings until safety tests had been completed.
Last night one of Britain's biggest unions - the GMB, led by John Edmonds - called for a full independent public inquiry into the safety of GM products "as the only way of restoring public confidence in GM produce".
The union's appeal was contained in letters to Mr Meacher and the Prince of Wales, a leading critic of GM. It claimed that 600,000 jobs were at risk unless consumer confidence was restored. The BSE crisis led to the lost of 37,000 jobs in agriculture, and the union said it did not want to see job losses among its members.
In a further blow to the Government, an all-party committee of peers and MPs yesterday criticised new regulations requiring labelling of GM products for failing to give adequate protection to consumers.
"People are in danger of purchasing GM foods without realising it. The government is at fault in law," said its chairman, Tory MP David Tredinnick. The regulations came into force on 19 March but provide no penalties for traders selling GM food without volunteering information on it unless consumers make enquiries.
The Group of Eight world leaders on Sunday called for an international inquiry into the safety of modified food.
In the face of pressure from at least five EU states, officials were last night trying to draft a statement designed to clarify Europe's opposition to the granting of new licenses until new regulations are in place.
France called for a "declaration, with the active cooperation of the [European] Commission, which would stop a member state being exposed to a legal challenge".
The French plan for a political statement would commit the EU to suspending any new GM crop approvals, or allow individual countries to block licences for environmental reasons. Peter Jorgensen, a spokesman for acting EU Environment Commissioner Ritt Bjerregaard, said: "The aim is a declaration which will underline what is current practice - that there isn't and won't be a sufficient majority for new products." France, Greece, Italy, Denmark and Luxembourg supported the temporary end to GM approvals.
The Commission has put new applications on hold after research indicated that a breed of butterfly might be endangered by the effects of GM.
However the British government argues that UK safeguards are satisfactory and says the French move would prevent any new decisions until 2002, in contravention of existing European law.
That would open up the prospect of legal action from producers in addition to trade objections through the World Trade Organisation. One British official said: "I do not think it would be credible for the Council of Ministers to say it would disobey community legislation."
The meeting in Luxembourg aimed to revise rules under the existing directive 90/220 for approving new GM crops, amid mounting public concern about the safety of the technology.
The British government was backing moves to tighten existing rules on risk assessment and monitoring, and to improve the labelling of products with a GM content.