NHS Western Isles is drawing up contingency plans for a strike by airport staff which could affect patients travelling for treatment.
Security workers at Highlands and Islands Airports Limited (Hial) will stage a 48-hour walkout from noon on April 7.
The action will affect services at airfields across the north of Scotland on Tuesday, Wednesday and Thursday next week.
Planes between Benbecula, Stornoway and Inverness provide essential connections for patients travelling from the Uists to hospital in Stornoway.
People requiring surgery or check-ups at Raigmore Hospital in the Highland capital also travel by air.
A Western Isles health board spokeswoman said: “It is likely that patient travel to the mainland and from Benbecula to Stornoway would be affected if flights had to be cancelled.”
She added: “We are currently considering all planned travel arrangements for the period of the proposed strike.
“We will be monitoring the situation and will make changes to patient travel arrangements in the event of flight cancellations, if necessary.”
No visiting services from mainland-based health consultants are planned on the strike dates, said the health board.
The spokeswoman added: “In the meantime, as there has been no indication to date that flights will be affected, patients should proceed with their planned arrangements.
“Should arrangements have to be altered in light of strike action and flight cancellations, patients will be contacted directly by the health board.”
In a ballot last week, 87% of Prospect union members who work for who work for the Airport Management Services Ltd (AMSL) voted in favour of a strike, on a turnout of 85%.
The union maintains the bulk of security workers receive “inferior terms for work of equal value” compared with other personnel.
Hial said its airports would open as normal despite the industrial action.
The firm said the union’s demand for a near-30% pay rise was excessive and “unrealistic” and it had taken steps to “improve pay, terms and conditions for AMSL staff and we are prepared to discuss further improvements with Prospect”.