France would reject British Prime Minister Theresa May's request for a three -month Brexit delay unless she offered a credible plan over how London will quit the bloc, formally scheduled for March 29, Foreign Affairs Minister Jean-Yves Le Drian said on Wednesday.

"We send a simple and clear message to the British... there are only two options to leave the European Union: ratify the agreement or an exit without accord," Le Drian told lawmakers.

"In case of a favorable vote, we'll be obviously open to technical extension for several weeks to allow British institutions to finalize the text's ratification. On the other hand, in the absence of a vote, the main scenario is a leave without agreement and we are ready for that," he added.

When questioned at the National Assembly, French top diplomat said the eurozone second key power, "will pay particular attention to the interests of the European Union," in considering an extension.

He noted the delay should aim at finalizing the ratification of withdrawal agreement which should not be re-negotiated and that Britain would not participate in the European election in May.

Le Drian also stressed that Paris would only agree to delay Brexit if London came with "sufficient guarantees to the European Council on her strategy's credibility."

After her departure deal was twice-rejected by parliament, British PM May earlier on Wednesday demanded President of the EU Council Donald Tusk to postpone Brexit until June 30.

She told MPs in the House of Commons that if the extension is agreed she plans to put her Brexit deal to MPs for a third vote.