Talks due on Caledonian MacBrayne shore staff's pay
About 70 Caledonian MacBrayne staff could see their pay reduced because of planned changes to allowances and bonuses.
The employees mainly work in booking offices and ports on the west coast.
CalMac is to meet the staff's union on Tuesday to discuss changes to weekend and shift allowances, night working payments and annual holiday bonuses.
The Scottish government has urged CalMac and the union to resolve the matter.
Highlands and Islands Labour MSP Rhoda Grant has written to Deputy First Minister Nicola Sturgeon and warned that anybody losing part of their pay will face hardship.
Western Isles SNP MSP Alasdair Allan said he was aware of discussions between CalMac and the unions.
He added: It would not be helpful for me to speculate about this while talks are ongoing.
"However, I have written to CalMac to ask them to clarify the situation and expressed the hope that a solution can be found that respects the situation of staff."
Bosses from the ferry operator and representatives of the shore staff union, the Transport and Salaried Staffs Association, are due to meet on Tuesday for talks.
A Scottish government spokesman said: "While this is a matter between the employer and the unions, we would urge both parties to seek an early resolution to avoid any impact on passenger services."