The number of jobs lost since April this year is five times higher than the government projected would be lost during the entire year, the Chartered Institue of Personnel and Development (CIPD) said.
The Office for Budget Responsibility (OBR) predicted in June 2010 that 610,000 public sector jobs would be lost between 2010-2015 because of the government's spending cuts. The OBR reduced that number in November last year to 410,000.
But the CIPD said that, based on the current rate of job cuts, the actual number of jobs lost in the public sector was likely to be 610,000: "exactly the same as the initial OBR projection".
The CIPDF has called on the government to "call a halt to public sector job cuts while the economy and labour market remain in the current fragile condition". A number of economists and opposition politicians agreed, calling on the government to rethink its programme of spending cuts.
But a spokesman for the treasury said that the cuts were necessary and essential to stimulate economic growth.
"Risks in the global economy make it even more essential to stick to the government's essential deficit reduction plan, which is supported by the International Monetary Fund, the OECD and the CBI", said the spokesman.
Economic growth has also been weaker than expected; figures released last week showed that the UK economy grew by 0.1% between April and June, slightly less than the previous estimate of 0.2 per cent.
The CIPD has warned that this slowth growth will lead to more jobs cuts. "Especially worrying is that public sector job losses in the second quarter of 2011 far exceeded net private sector job creation, which suggests that the slowdown in economic growth since the autumn of 2010 is gradually sapping the strength of those parts of the economy that were creating jobs in the initial part of the recovery."
The treasury have downplayed the public sector job losses however, and said the losses are outweighed by the creation of private sector jobs.
"Half a million private sector jobs were created last year and the independent OBR has forecast that there will be 900,000 more jobs created in the private sector than lost in the public sector by 2015," the Treasury spokesman said.
The OBR is a government-appointed body formed last year to make an independent assessment of the government's finances and of the economy.