Caledonian MacBrayne staff moved into Portakabins and other temporary offices on Monday to allow contractors to begin working on the inside of the building.

The contract for the work, which is being carried out by A. Alexander & Son at a cost of £145,000, is due to last 12 weeks, with completion due in early April - which leaves almost no room for any unexpected disruption if visitors to Bute during the busy spring holiday period are to be unaffected.

The start of work on the pier building comes almost a year after transport minister Stewart Stevenson visited Rothesay to officially open the £13 million redevelopment, which includes a new end-loading linkspan for CalMac's Wemyss Bay ferry service, a swing bridge between the terminal building and the mid pier, and strengthening work and installation of pontoons in the inner harbour.

The pier building's revamp was delayed after community representatives said that after three summers of major upheaval in the harbour area, they did not want the final part of the work to be done during the island's main tourist season.

The project includes the refurbishment of reception facilities and staff accommodation for CalMac, and of the building's public toilets; the creation of a new toilet facility for external users from the marina; new doors to improve access to and from the terminal building; and a general refurbishment of all the associated services.

A spokeswoman for Argyll and Bute Council said the temporary waiting, booking and toilet facilities already in place meant the effect on day-to-day passengers should be negligible, and that the work would be completed in its entirety before the newly-refurbished building opens its doors.

Bute Community Council's transport representative, Frank Baxter, said: "Building work encroaching on to the Easter weekend would be a major disaster if it did occur.

"Unfortunately we've not got a crystal ball, and I would like to hope that there is a contingency plan to minimise disruption if there is a delay, but with the amount of work that is required I would agree that there are lots of opportunities for things to run late.

"It wouldn't look very good for visitors coming off the ferry at Easter if they're having to move around or through a building site again."

Island councillor Len Scoullar told us he had hoped the work could get under way before Christmas - but that the refurbishment of the building, which will also include toilet and shower facilities for visiting yachtsmen and their passengers, was still much needed.

"Apparently, getting a contractor to begin work in December and work for three weeks before having to stop for a fortnight over Christmas is not easy," Cllr Scoullar said.

"It is a 12-week contract and I would hope the work can be completed before it has an effect on the island's tourist season.

"The toilet and shower facilities for visiting yachts have been badly needed for some time and I'm delighted they are being provided as part of the contract."

Brian Fulton, CalMac's upper Clyde regional manager, said the company's main concern was the smooth operation of the ferry service, and he was hopeful there would be no day-to-day disruption.