PORTLAND  — Sen. Susan Collins of Maine is expressing skepticism over the U.S. Postal Service’s proposal to cut Saturday mail delivery to fend off huge budget shortfalls.

Collins is the ranking member of the Senate Homeland Security and Governmental Affairs Committee, which has oversight over the postal service.

She said the postal service should focus on serving its customers better, attracting new customers and increasing volume — not on cutting services.

She said businesses will seek other alternatives if mailing days are cut, which will further erode the postal service’s shrinking mail volume and lead to more severe financial problems.