A second Royal Navy warship HMS Richmond has been deployed to the Mediterranean to help patrol the coast off Libya as part of an EU bid to stop human traffickers smuggling refugees to Europe.
HMS Enterprise is already stationed in the region to gather intelligence but was called into action last month to save nearly 400 refugees and migrants after Italian authorities were overwhelmed.
HMS Richmond's commanding officer will have powers to board and seize boats suspected to be used in people smuggling following the adoption of a United Nations Security Council resolution, the MoD said.
Defence Secretary Michael Fallon vowing to "hit the traffickers hard" adding:
HMS Enterprise replaced HMS Bulwark, which saved 3,000 lives in the Mediterranean, in July as part of a wider EU mission to detect and stop people-smuggling gangs.
More than 600,000 migrants have made the perilous journey to the EU by boat this year alone, often paying thousands of pounds to traffickers.
UN sources estimate more than 3,000 people have died trying to make the crossing so far this year.
The announcement also comes after four boats carrying migrants landed at the RAF air base at Akrotiri in Cyprus on Wednesday.