STENA Line is set to introduce a third new ferry to the Irish Sea as part of its fleet and port redevelopment.

The Swedish firm said the ferry Stena Embla, which can carry 120 cars and 1,000 people, has begun a six-week journey to the British Isles following its acquisition from the CMI Jinling Weihai Shipyard in China.

It is the third of five more fuel-efficient E-Flexer vessels being constructed at the Chinese shipyard, with the first two ferries in operation since earlier this year.

The Embla is expected to start sailing on the ferry lines between Great Britain and Ireland in January.

It marks the end of an extensive modernisation of the company’s seven-year development programme totalling £400m investment in new ferries and port infrastructure.

"With the new crew in place they can start the long journey to the Irish Sea, where Stena Embla will begin serving customers in the UK and Ireland," said Stena Line COO Peter Arvidsson.

At 215 metres in length, Stena Embla will provide freight capacity of 3,100 lane metres, meaning a 40 per cent increase in freight tonnage.

The remaining two E-Flexer vessels under construction in China are even larger versions with a total length of 240 metres.

Stena Line CEO, Niclas Mårtensson said: “While delivery of the vessel marks the end of a very tough period for us, it also marks the completion of a very significant investment in our Irish Sea operations.

"It reflects our strong support for the region that will see three of the world’s most modern ferries operating between Britain and Ireland.

"We recently celebrated the 25th anniversary of the relocation of our Northern Ireland operations to Belfast and 25 years since we commenced the Holyhead to Dublin route.

"Our three new ferries in the region is a sign of our strong commitment to another 25 years on the Irish Sea."