Reports that creditors had rejected a potential rescue plan sent Carillion's shares down by more than 28% on Friday.
These include a new £745 million Aberdeen bypass and plans to extend platforms at Edinburgh Waverley station to make way for longer electric trains. Its market value of 64 million pounds compares with debt and liabilities of 1.5 billion pounds, according to analysts.
The company provides vital services to hundreds of schools. "The collapse of Carillion could provoke a serious crisis".
The company needs £300m of emergency funding and lenders are under pressure from the Government to keep the company afloat.
"The Government knows the disastrous consequences of a Carillion collapse so is doing all it can to avoid that happening".
The Wolverhampton-based group is the second-largest supplier to Network Rail and maintains approximately half of the UK's prisons as well as roughly 50,000 homes for the Ministry of Defence.
The firm has seen its share price plunge almost 80 per cent in the past six months after making a string of profit warnings and breaching its financial covenants.
The crisis-hit construction firm, one of the largest suppliers of services to the public sector, has called on the government to step in to reduce the financial burden of a string of failed projects around the country.
A spokesman for the Scottish government said: "We continue to liaise with United Kingdom government colleagues to monitor and mitigate service risks associated with Carillion's financial situation".
"You can see that one the one hand, it's in everybody's best interest that Carillion continues, but at the same time it's hard to chart a way forward".
Transport Scotland said that Carillion had "no intention of withdrawing" from the AWPR project, and that the consortium delivering the route "remains committed to completing it in accordance with the contract". The long-awaited route is due to be finished this year following lengthy delays.
Sky News has learnt that senior civil servants from the Cabinet Office are expected to attend an emergency summit that will also include representatives from The Pensions Regulator (TPR), Pension Protection Fund (PPF), Carillion's pension trustees and an assortment of City advisers.
Unless that funding materialises - either from commercial lenders or in the form of emergency Government support - Carillion would be likely to crash into administration, threatening the jobs of at least some of the 19,500 people it employs in the UK.
Ministers met Thursday to discuss the issue, and there will be "ongoing meetings", Blain said.
Carillion said that as part of its engagement with stakeholders, including banks, it is in constructive dialogue in relation to additional short-term financing while the longer term discussions are continuing.