The three-year agreement comprises a £40m revolving credit facility and £20m asset finance line.
Murphy, which turns over more than £700m a year, began working with Lloyds last year.
David Burke, chief financial officer at Murphy, said: “We have continued to win contracts and new clients during the first half of 2019.
“This partnership will help us to continue to deliver and provides us with the confidence and flexibility to invest in world-class assets, grow our business in the appropriate way and support our approach to rigorously manage our balance sheet.”
Among the new deals are major contracts with National Grid
to construct 10km of underground power cables for the Hinkley Point C new nuclear project and a £24m contract for a new substation near Barking in East London.
Steven Kew, relationship director for infrastructure and industrials, Large Corporates at Lloyds Bank Commercial Banking, said: “Murphy continues to be at the forefront of some of the UK’s most exciting infrastructure projects and this investment will enable them to power on.
“This partnership will give Murphy added reassurance to continue developing its offering for its expanding customer base.”