The TUC is warning long-term unemployment those without a job for over a year will rise to 700,000 in 2009.
The body representing UK unions is warning while employment levels are at record highs, the proportion of those in long-term unemployment is rising.
The TUC also predicts total unemployment will rise from the current level of 1.7 million to over two million by the end of 2009.
On Monday the CBI representing employers forecast unemployment would rise to 2.1 million next year, while last week David Blanchflower at the Bank of England warned jobless numbers would rise still further.
TUC general secretary Brendan Barber said: "Employment levels have remained high despite the recent economic turbulence and are nowhere near the dark days of 1992, when nearly three million people were unemployed.
"However, the TUC is concerned that unemployment has been sneaking up in the last few months and it's up to unions, employers and the government to halt and reverse this trend as soon as possible."
The body is warning the government's latest welfare reforms would by pushing more people onto job seekers' allowance.
"With unemployment rising, people are looking to the government for a response and economic measures will be far more welcome than yet another round of welfare reforms," Mr Barber said.
"All the tabloid-friendly tough talk on benefit claimants will backfire on the government when the numbers of people out of work, off benefits and sliding further into poverty start to mount."
TUC head of economics Adam Lent called on the Bank of England to cut interest rates to boost the economy and reduce joblessness.
"Poor growth and falling consumer confidence are a far greater risk to the economy than inflation, which is still relatively low," he said.
"The Bank of England can play a key role in helping to reinvigorate the economy by cutting interest rates this month."