The group behind the Corrib Gas project is to invest another €800m to bring it to completion between now and late 2014.
Shell E&P Ireland claims the investment will sustain 700 direct jobs and 750 indirect jobs in that period, and that, when complete, the project will supply 60% of Ireland's gas needs.
The controversial Corrib Gas project has been under construction since 2004. Since work began, trenchant opposition from groups opposed to the plan has kept it in the headlines.
But Shell now says it will soon begin the final phase of the project.
As the sea bed wells and pipeline are complete - and the terminal practically complete - the final phase of work will focus on connecting the deep sea pipe to the terminal via a second pipeline to be contained in a tunnel under Sruwaddacon Bay.