BRUSSELS (AFP) - The EU rejected on Wednesday Britain's claims that its new plan to deal with migrants crossing the Mediterranean would put more lives at risk, saying that taking no action was more dangerous.

"I wonder how anyone could maintain that this could make the situation worse," European Commission First Vice President Frans Timmermans told a press conference as he launched the blueprint.

British interior minister Theresa May called Wednesday for some migrants fleeing conflict and poverty in North Africa and the Middle East to be sent back, rejecting the EU policy of dealing with asylum claims of those who are rescued in the Mediterranean.

She also said that London would take no part in the Commission's plan to distribute refugees around the 28-nation EU by a quota system which is aimed at reducing the burden on countries like Italy and Greece where many migrants arrive.

"I have the highest regard for British intelligence but I am not sure Theresa May had already read all the plans we have made, so I'll wait for the British government to have time to appraise our plans," said Dutchman Timmermans, the right-hand man to Commission chief Jean-Claude Juncker.

"First of all what will make the situation worse is doing nothing, maintaining the present system," Timmermans.

"If we then do nothing, we make the situation worse for people in trouble and lose credibility in the eyes of our citizens who have demamded that we do something about the tragedies in the Mediterranean."