Ministers said that the strikes – set to be the biggest walk-out in decades – could cost the economy up to £500m and cause job losses.
The ministers in charge of pensions, Francis Maude and Danny Alexander said Wednesday’s strikes would cause a “significant hit to the economy at a very challenging time”.
They urged public sector staff to stay in work, rather than join the planned walk out by over 2 million workers.
But unions responded, saying the government was trying to use public sector workers as a “scapegoat” for the state of the economy and accused ministers of “fantasy economics”.
Maude said economic output would be lower if people didn’t turn up for work, which would cause loss of employment.
He said: “Exactly what that relationship is very hard to anticipate but if we lose a big chunk of output it is hard to see how that does not translate into fewer jobs.”
Brendan Barber, the TUC general secretary hit back, saying: “While the strike on 30 November will obviously cause disruption, the figures suggested by ministers are fantasy economics.
“This is the clearest sign yet that next week’s autumn statement will be a damp squib and the government is using the strike as yet another desperate excuse.
“Blaming the weather, the royal wedding and now scapegoating hardworking teachers, nurses and dinner ladies for the UK’s economic woes is pretty poor from a government that has presided over record unemployment and the weakest economic recovery for a century.”
Unions say proposals requiring their members to work longer before they get their pension are unfair, but the government says they need to change to reduce the cost to the taxpayer as people are living longer.
Alexander said there was “no more money on the table” to calm the row over pension reforms.