The man was feeding paper into a paper machine on 13 January when he became trapped.

A spokesman for International Paper said: "The machine operator involved received first aid treatment for his injuries on-site and was later transferred by ambulance to hospital in Aberdeen."

He said that the accident was immediately reported to the Health and Safety Executive and that an inspector would visit the mill in due course.

Production on the paper machine was halted for around three hours and an internal investigation into the accident is under way.

The spokesman said: "International Paper places the highest priority on employee safety and serious reportable accidents are extremely rare."

The Aberdeenshire-based plant is the global paper and packaging company's only non-integrated fine paper mill and it produces 250,000 tonnes of uncoated freesheet paper annually.

In October last year, the company entered into consultation with the 371 staff at the mill and began a consultation process on strategic alternatives for its future, although the mill remains in production.

An International Paper spokesman said that since then, weekly meetings have been held at the company but no viable outcome has been achieved. The process will continue until the middle of February, he added.