The main transport workers' union has received a "cast-iron assurance" that publicly run ferry services off the west of Scotland will not be privatised.
The RMT feared that Clyde and Hebrides ferry routes, run by state-owned operator CalMac Ferries, would be broken up and sold off to private companies, with knock-on implications for workers' terms and conditions.
Constructive talks have now held with Transport Minister Keith Brown, the RMT said.
"We now have a cast-iron assurance that there will be no unbundling of the CalMac routes in order to prime them up for privatisation," general secretary Bob Crow said.
This stance was confirmed by Alex Salmond at First Minister's Questions, Mr Crow believes.
Mr Salmond told MSPs that the Scottish Government has "no plans to unbundle the Clyde and Hebrides ferry service" because "the case for unbundling, in our estimation, has not been made."
Responding to a question by Labour MSP Richard Baker, the First Minister said: "The tendering of the Clyde and Hebrides lifeline ferry services is required to protect these vital services.
"Given that there can be no disagreement that the tendering process is inevitable and given that I have just given him an indication of the Government's view on unbundling, which should give him and the workers much security, then I hope he can see that this chamber should be united in protecting our lifeline ferry services."
The RMT is still awaiting a written response from the Transport Minister on other points in dispute, notably pensions and the protection of workplace rights, Mr Crow said.
"While we have made some meaningful progress today, RMT's campaign to defend Scottish ferries from privatisation and attacks on the workforce goes on, and we intend to keep this issue right at the top of the Scottish political agenda," he said.