The pay of public sector workers has fallen below that of employees in private firms after years of wage restraint because of Government policies, official figures have shown.
On average, pay in the public sector was between 1.3% and 2.4% lower in April 2013 following years of wages being held down.
The Office for National Statistics (ONS) said the biggest pay difference in favour of public sector workers was in Northern Ireland, compared with London where staff in private firms earned more.
Public sector workers on low pay earned more than low-paid employees in private firms, but the position was reversed when comparing high earners.
TUC general secretary Frances O'Grady said: "Years of freezes, real-terms pay cuts and rounds of redundancies have left public servants facing a sharp squeeze in their living standards.
"Not only do public sector workers now earn less than equivalent staff in the private sector, they also face greater job insecurity as hundreds of thousands are set to go in the coming years.
"Top earners in the private sector enjoy a huge wage premium over the public sector but the lowest paid private sector workers do even worse than their public sector counterparts. If private businesses paid their lowest paid staff more fairly we'd make huge inroads into reducing in-work poverty."
Dave Prentis, general secretary of the Unison union, said: " The pay freeze and squeeze has hit public service workers hard, leaving many struggling to get by. The pay cap, coupled with inflation means that for many workers the value of their pay has fallen by 16% since 2010 - a massive pay cut.
"However, these ONS comparisons do not shed any light on the harsh reality of low pay for workers across the country in the public and private sectors caused by this Government's austerity agenda.
"It is clear from the latest round of bankers╣ bonuses that those at the top are thriving at the expense of ordinary workers. The rise in in-work poverty, zero- hours contracts, payday loans and the massive increase in people using food banks are all testament to workers struggling to make ends meet."