Ireland has agreed to accept an additional 300 migrants under a new EU plan to tackle the Mediterranean refugee crisis. 

The European Commission has proposed new measures, including a plan for national quotas, aiming to bring 20,000 refugees to Europe in the next two years at a cost of €50m. 

Germany will take the highest number of refugees, followed by France, Italy and Spain. 

Britain has criticised the plan and chosen not to participate.

Ireland also had a choice to opt out, based on protocols agreed in the Lisbon treaty, but has decided to take more than the 272 people expected by the proposals. 

Ireland has already committed to resettling 220 people, mainly Syrian, up to 2016.

The EU is trying to put in place a fairer way to resettle asylum-seekers who survive the dangerous crossing, at a time when anti-immigrant parties are on the rise across the continent.

Italy and other southern European countries are clamouring for EU help to deal with the influx but, while Italy, Germany and Austria backed the quota system, some EU states are opposed.

"No country should be left alone to address huge migratory pressures," European Commission President Jean-Claude Juncker said on his Twitter account after the proposals were published.

Hours before the plans were unveiled, British Home Secretary Theresa May criticised the EU's approach, saying that by not sending economic migrants back, the bloc was encouraging them to come.

The EU has rejected Ms May’s claims, made in an article in The Times newspaper, saying that taking no action was more dangerous.

Speaking to a press conference, European Commission First Vice President Frans Timmermans said "What will make the situation worse is doing nothing... I wonder how anyone could maintain that this could make the situation worse."

Mr Timmermans, also said returning some migrants was still part of the EU's policy and Ms May "can rest assured" that not all refugees will be granted asylum.

Ireland, Britain and Denmark have exemptions on matters concerning asylum, immigration, visas and external border controls based on protocols agreed in the Lisbon treaty.