The UK government has "clearly failed" to make a convincing case for the closure of Coastguard stations, a committee of MPs has said.
Westminster's Scottish affairs committee said more must be done to reassure the public that services would remain up to scratch.
A decision was made to close Clyde and Forth Coastguard stations and others around Britain.
UK ministers said the reforms followed extensive public consultation.
In a report on the closures, the Commons committee said it was "deeply concerned" of claims that frontline workers felt excluded from the process.
MPs said there had been "no satisfactory explanation" for the decision to close the Clyde and Forth stations.
The UK government is closing eight coastguard stations as part of a modernisation plan, including Great Yarmouth, Liverpool, Thames, Swansea, and Portland.
The Clyde and Forth stations are due to close by the end of the year.
Centres in Belfast and Stornoway will, according to the UK government, take on the Clyde station's operations, without affecting safety.
And responsibilities for the Forth operations will transfer to Aberdeen and Shetland.
Both the government and Maritime and Coastguard Agency assured the Committee that "robust and extensive testing" was being done before the closure of Clyde Maritime Rescue Co-ordination Centre, to ensure the stations taking over its area of responsibility would do so seamlessly and continue to provide the level of search and rescue cover which the public had a right to expect.
The committee said it wanted an assurance after 31 December that the Scottish coastline was still being served to the same high standard as before.