The new 800 metre jetty at Holmsgarth North will provide deeper berthing and and a bigger working area for the local fishing fleet.
Tulloch will start on site before Christmas creating 50 jobs with completion due in autumn 2016.
The design of the jetty is by civil engineers Arch Henderson LLP and they will also project manager the construction.
Port Authority Chief Executive Sandra Laurenson, said: “The jetty will be a significant addition to our resources and another example of our versatile facilities.
“While principally benefiting the fishing industry, it will also serve the offshore sector, underlining our commitment to both.”