Keith Brown, who is now justice secretary, but was previously the minister responsible for infrastructure, was strongly criticised by the Scottish Parliament’s public audit committee. It questioned whether his behaviour breached the ministerial code.
Mr Brown previously told MSPs he did not “have any further information to provide” after being pressed for more details.
There has been a long-running row over the construction of two CalMac ferries, the Glen Sannox and the as-yet-unnamed hull 802, which are now more than three times over budget and years late. One is destined for the Arran route and the other will serve Skye, North Uist and Harris.
Their botched construction at the Ferguson Marine shipyard in Port Glasgow is the subject of a probe by the public audit committee, which is led by former Scottish Labour leader Richard Leonard.
Mr Brown, who is also the deputy leader of the SNP, was asked for details of the information shared with him by then transport minister Derek Mackay, as well as any action he took following concerns raised by Caledonian Maritime Assets (CMAL), which owns the ports, ferries, harbours and infrastructure.
In a scathing letter to Mr Brown on behalf of the committee, Mr Leonard said: “The committee finds your responses to be both unsatisfactory and evasive. By way of example, we asked for details of the information that was shared with you by the former minister for transport and the islands, before he went on leave, about the status of the procurement of the ferry vessels, including any concerns.
"You failed to answer that specific question, referring instead to a submission you received from Transport Scotland when the minister was on leave. This was not information we asked for, as it is already in the public domain.
“The committee is extremely disappointed by your failure, once again, to provide sufficient answers to the questions we sought to help inform our scrutiny despite our best efforts. Your unwillingness to engage constructively with the committee is disrespectful to both the committee and the Parliament.”
Mr Leonard highlighted the requirements outlined in the Scottish ministerial code, including that ministers have a duty to account for their policies, actions and decisions, and they should be “as open as possible with the Parliament and the public”.
He said: “We now find ourselves in the regrettable position of questioning whether these requirements have been followed in this case. The committee is now turning its attention to producing a report of our scrutiny, which will be published in the coming months.
"I expect we will wish to consider in this report the level of engagement we have had with Scottish ministers and stakeholders during the course of our work, and how this is reflected in our conclusions and recommendations. The committee would consider any further evidence you wish to give. The deadline is January 6, 2023.”
Scottish Conservative transport spokesman Graham Simpson insisted Mr Brown “must come clean”, adding: “He cannot continue to dodge critical questions about what he knew and when in relation to his Government’s ferries fiasco.
“His lack of detailed responses are not only an insult to the committee, they are the latest example of a senior SNP figure believing they are above parliamentary scrutiny.”
The Scottish Government was approached for comment.