BRUSSELS—The European Union is set to put in place a plan that would make it easier for the bloc’s governments to block Covid-19 vaccine exports, raising the stakes in a standoff over vaccine exports with the U.K.

At a virtual summit on Thursday and Friday, leaders are expected to give their backing to a proposal announced on Wednesday by the European Commission, the bloc’s executive, with a formal signoff coming in the next few weeks. However, the real test of the move’s significance will be how actively leaders decide the proposed powers should be used.

With the bloc’s vaccine rollout going far more slowly than those in the U.K. and U.S., the commission—which was given responsibility for negotiating vaccine contracts—and national governments are facing mounting public anger. Member states including Germany and France have announced new lockdowns in the face of rising coronavirus infections.

The chief target of the bloc’s ire has been the U.K., which left the EU last year. It has imported millions of doses from the bloc but hasn’t exported any.