An announcement from steel firm Tata is expected on Tuesday on the future of its plants in Motherwell, Cambuslang and Scunthorpe in North Lincolnshire.
It is believed about 1,200 jobs will be affected, including 400 in Scotland.
The Scottish government said it continued to "explore all options" to find a viable future for Tata's sites.
First Minister Nicola Sturgeon told her party conference in Aberdeen on Saturday that "if our worst fears are realised", she would immediately establish a task force to work with the company, the trade unions and local authorities.
Tata employs about 70 people at its Clydebridge plant in Cambuslang, with the remainder of its Scottish workforce based at its Dalzell plate rolling works in Motherwell.
Trade union Community, which represents steel workers, said it wanted any task force to support a programme which would keep the plants open while a long-term solution was sought.
Assistant general secretary John Park said: "We are in the middle of the worst slump in steel prices in living memory and it is essential we maintain our capacity to produce steel in Scotland.
"We welcome Nicola Sturgeon's announcement of a steel task force, but it cannot simply be an exercise in managing decline.
"If the Scottish steel industry is to have a future, then Nicola Sturgeon must ensure the strategic assets at Dalzell and Clydebridge are maintained."
Mr Park also called for a "proper industrial strategy" for the sector to be developed.
He added: "For steel to have that future we must secure the skills of the men and women who work in the industry.
"That is why we are calling on the Scottish government to support short-time working programme, should that be necessary over the coming weeks."
A Scottish government spokeswoman said: "Since last year, when Tata Steel first announced the potential sale of its long products division, the Scottish government and its agencies have been in constant contact with both Tata Steel and with the trades unions.
"We continue to be in contact to explore all possible options to find a viable future for the company's sites in Scotland."
Labour MSP John Pentland said: "When Grangemouth, Fergusons and Prestwick Airport were at risk, the Scottish government stepped in to provide support and to secure jobs.
"They need to do the same now - anything less will not be acceptable.
"This is an iconic industry for our nation and the men and women who work at Clydesdale and Dalzell deserve all possible support."
Steel workers have called on Scottish ministers to help secure the industry's future by backing a "short-time working programme" if plant closures go ahead.