The money is being provided by the Welsh Government under a 22-year “mortgage-style” agreement to help offset cuts in public spending.
Over the next three years it is predicted the funding scheme will bring in about £170m for highways maintenance.
The repayments will cost the Welsh government about £240m over 22 years. It is setting aside £4m in the first year of the Local Government Borrowing Initiative.
Welsh Local Government Association regeneration director Tim Peppin told the BBC: “It’s very much a question of seeing how this works, but it has the potential to be used in other areas.
“Some people in authorities have raised concerns, but there’s a world of difference between borrowing to finance straight consumption and borrowing to put the main bedrock of the economy into shape.”
Finance minister Jane Hutt said: “We want to help councils address revenue pressures, and see them undertake new and necessary capital investment in our highways.
“By providing £4m in the first year of the scheme local authorities will be boosting their capital spending by £60m this year resulting in immediate improvements to our roads and highways, and creating or safeguarding around 900 jobs.
“Without our effective collaboration, this kind of investment would, quite simply, have been unaffordable.”