The owner of Ferguson Marine has clashed with the Scottish government over plans to nationalise the shipyard.
Jim McColl said there was “no economic sense” in the idea, and that it would “damage the economy”.
Speaking to the Mail on Sunday, he also accused ministers of “abusing their power” in the way they have handled their long-running dispute.
The Scottish government responded that Mr McColl’s own rescue plan “had a number of serious risks”.
The Port Glasgow site, which employs about 350 staff, is due to enter administration.
Finance Secretary Derek Mackay has said taking the beleaguered yard into public ownership was an option.
It comes amid a very public row between Mr McColl and the Scottish government over a contract to build two ferries.
The £97m deal for CalMac is behind schedule and considerably over budget.
Ferguson has said it expects to lose nearly £40m on the ferry deal, which is being procured through the public-sector agency CMAL.
The Scottish government said Mr McColl’s proposal to salvage the contract would not have put any of his firm’s money into the yard.
A government spokesman said: “It offered no certainty on the overall final cost of both vessels and saw no money from Clyde Blowers Capital themselves being invested.”
The spokesman added the proposal – understood to have involved the Scottish government taking an equity stake in the business – could have been unlawful.
The public fall-out is between ministers and a businessman who was close to the SNP administration.
Mr McColl is reputed to be a billionaire, and is one of First Minister Nicola Sturgeon’s council of economic advisers.
Five years ago, he helped the government politically, with a deal to take the Ferguson shipyard out of administration, averting closure in the days before the independence referendum.
On Friday Mr McColl, along with fellow directors of Ferguson Marine Engineering Ltd, served notice of intent to put the company into administration by next Friday.
The £97m fixed price contract for the two CalMac ferries is understood to have doubled in cost, at least partly due to the complexity of designing and installing an innovative hybrid, dual-fuel engine.
The Scottish government has been working over the weekend on its response to the administration warning. A letter was to be sent by Monday morning setting out how ministers intended to proceed.
Talks are expected from Monday between lawyers and advisers and a solution is expected by midweek.
Last night, the Scottish government repeated its pledge to safeguard jobs for the 350 people who work at the Inverclyde yard, and to complete the ships.
It said that it had been working on the basis of no additional funding going into the business from Ferguson or Jim McColl’s investment firm Clyde Blowers Capital.
A spokesman said: “We have been actively considering other options, including public ownership and remain keen to reach a conclusion on this matter.
“We also remain open to considering viable alternative options and will continue to work with all partners to reach a constructive solution that can deliver both the vessels and safeguard jobs for those who work in the yard.”