It follows yesterday's announcement that the firm's London to Edinburgh line had been suspended and taken over by the Government.
National Express also run NE East Anglia and C2C services in Essex and yesterday the Government appeared on the brink of re-nationalising them too.
Essex commuter chief David Bigg encouraged the Department of Transport to step in.
He said: "The best option at the moment would be to re-nationalise the railways.
"Passenger numbers are dropping and the operating companies still have to pay large amounts into the Treasury before they can pay their shareholders. That's not adding up at the moment."
Yesterday the Government said NE was not meeting its franchise terms for the London to Edinburgh line and suspended the franchise.
A Department of Transport spokesman said it was "Looking at options" for the franchises in Essex, including the Stansted Express, and C2C services in south Essex.
He added: "The franchise rules say if a company defaults we have the right to remove all its franchises but we are keeping our options open."
However, National Express says the Government would not be allowed to re-nationalise its Essex services after what has happened.