LDV, which employs 850, had hoped to restart production in July
Managers and workers at Birmingham van maker LDV have been forced to cancel a lobby of parliament because of the cabinet reshuffle.
The group was told there would be no ministers to meet them because of events at Westminster.
Some 850 jobs are under threat at the Washwood Heath plant, after a deal with Malaysian firm Weststar collapsed at the last minute.
LDV's owners are expected to put the firm into administration on Monday.
Guy Jones, LDV's marketing director, said they felt let down by events that had forced them to call off the lobby.
He said they had been planning to ask for a £60m loan to secure the firm, which would cost the state much less than the collapse of the business.
The firm hopes the government will agree to the plan, even at this late stage in negotiations.
"The Government may be imploding," Mr Jones told BBC WM, "but there are thousands of jobs at stake here."
A spokesman for Liam Byrne, Labour MP for Birmingham Hodge Hill, said: "Liam Byrne is in Westminster, and is standing ready to meet LDV workers, as part of a number of actions he's taking today to try to help LDV."
Last month Weststar agreed a deal to acquire the company and the government pledged a £5m four-week loan until the deal was sealed.
The firm's plant has been at a near-standstill since before the end of 2008, while intensive efforts were made to save it.
In addition to the workforce, LDV employs 1,200 people in dealerships and is a major customer for local suppliers.
When Weststar initially agreed to buy the company from its Russian owners, it was it planned to restart production in July.
The firm said it intended to maintain production at the company's plant in Birmingham, but also to expand manufacturing in Malaysia.