Workers at two mines in north-west Tasmania have rejected calls for a pay cut.

Barminco – operator of the Rosebery and Renison mines - wants to expenses by $18 million this financial year.

It asked its 200 employees to take a 10 per cent pay cut, but after negotiations with the Australian Workers Union, the proposal was rejected.

The union has referred the matter to the Fair Work Commission.

AWU deputy branch secretary Robert Flanagan said despite the most recent package offered was an improvement on the earlier rejected plans, but workers were still concerned about some aspects.

“There were aspects that would have had a direct impact on their earnings which employees were not prepared to endorse,” he told reporters.

“The impact varies according to the occupations that employees perform but at the end of the day, people were not prepared to lose earnings.

“The modified proposal had significantly less impact for some than was originally proposed but the impact was still considered by the employees [as] something they were unable to sustain.”

Mr Flanagan said it was unclear whether workers earning above the enterprise agreement level would still be asked to take a 10 per cent pay cut.