Eddie Stobart is blaming "internal systems" for a failure that has left its drivers out of pocket.
The haulage company says its £60m purchase of James Irlam last year and subsequent integration into its business has created issues with the payroll system and it has been forced to bring in extra resources to solve the problem.
Commercial Motor has spoken to one employee who claims there might be as many as 100 affected drivers. He says: "It's a big issue at the moment. For some unknown reason the pay office are missing information week in, week out. It's absolutely poor to be honest. There's a breakdown in the system and it's been going on for quite a few weeks. I am surprised it hasn't yet been put right."
Another driver claims the company is ringing him every day in order to clarify how much driving he is doing and therefore pay he is owed.
A Stobart spokeswoman says: "Due to the transition of James Irlam into Eddie Stobart, there have been some issues with the payroll system. This affects only a very small percentage of the group's 5,000 employees.
"The company is working hard to address these issues and extra resources have been drafted in. Working with employees, the group will resolve matters as quickly as possible."