The 8,000 sq ft development beside the A189 near North Seaton includes a petrol filling station, convenience store, a drive-through Starbucks outlet plus Subway and Cooplands.
It has created 45 full and part time roles plus important amenities and services.
The investment from EG Group marks another step forward in the development of Ashwood Business Park.
Last year, £2.7million was secured from Advance Northumberland, Northumberland County Council and the North East LEP for infrastructure improvements to encourage further inward investment and growth projects at the site.
Cllr Jeff Watson, Chair of Advance Northumberland said, “We’re delighted that EG Group has brought new amenities at Ashwood Business Park – and it’s fantastic to be welcoming a company of their calibre to the site.
“The petrol station, retail offering and foodservice offer from EG Group will enhance Ashwood Business Park’s infrastructure and further boost its appeal to investors looking for a well-connected location within a vibrant manufacturing cluster and with a highly skilled workforce on the doorstep.
“Ashwood Business Park is a place where businesses can develop and expand, and we have seen from the success of AkzoNobel and Bernicia Homes how companies can thrive at this prime location.”
Neil Findlay, UK Development Director at EG Group said: “We are delighted to have opened our brand new development and to have worked with Advance Northumberland on this development site within the Ashwood Business Park.
"Working in close partnership with Advance we firmly believe that our best in class roadside services will be an asset to the park and the wider Ashington area.”
Helen Golightly OBE, Chief Executive at the North East LEP said: “The arrival of EG Group to Ashwood Business Park will further cement this Enterprise Zone as a very attractive prospect for investors.
"The site is in a prime location and businesses locating there will benefit from tax breaks and a range of interventions – we look forward to this site attracting many more businesses and creating more and better jobs for our residents.”