A rail operator is planning to close ticket offices and install more machines at stations, according to a union.
The Rail, Maritime and Transport union said it had been told that Greater Anglia is planning a programme of ticket office closures across its network.
The company has told RMT officials it is planning to have seven traditional ticket offices at London Liverpool Street, Colchester, Norwich, Cambridge, Chelmsford, Ipswich and Stansted Airport, compared with the current 64, said the union.
Station ticket offices will close during the next year in three stages, said the RMT.
General secretary Mick Cash said: "The union is appalled at this planned attack on ticket offices and station staff across the Greater Anglia franchise which would wipe out the vast bulk of these vital passenger services over the next year.
"The union will fight with every tool at our disposal to halt these disastrous plans which are all about cutting public services to pump up private profits.
"This is all part and parcel of a national drive to de-staff our trains and stations as the private train companies look to smuggle in a faceless railway in a dash to fatten up their own profit margins.
"RMT is calling on the public and politicians to join with us in a mass campaign to halt this ticket office massacre."
A Greater Anglia spokesman said: "We have no plans to reduce the number of Greater Anglia ticket offices to seven.
"However, we are currently reviewing responses to a public consultation about proposals to close seven little-used ticket offices.
"There are no current proposals to close any other ticket offices. We will continue to consult with our colleagues and the trades unions on any proposed changes to ticket office arrangements."