SAINT JOHN, N.B. -- Irving Oil says Canada's largest oil refinery will begin a $135 million tune-up next week that will utilize 2,400 workers over six weeks.

Mark Sherman, chief operating officer at Irving Oil, says workers will undertake maintenance and infrastructure projects to increase the Saint John, N.B., refinery's efficiency and performance.

Irving Oil says the project is expected to result in more than $15 million in benefits for the local economy.

The Saint John refinery has reached production rates in excess of 320,000 barrels per day.

It exports over 80 per cent of its production to the United States.