The Government has praised private companies for creating jobs, but admitted there were "tough challenges" ahead as unemployment increased for the first time in a year.
The jobless total jumped by 7,000 to 2.52 million, ending a run of reductions, with all the increase caused by more 18 to 24-year-olds becoming unemployed.
The total is still 152,000 lower than a year ago, while the number of people claiming jobseeker's allowance fell in February by 1,500 to 1.54 million, the fourth consecutive monthly reduction.
There were 993,000 jobless 16 to 24-year-olds in the latest quarter to January, up by 48,000 from the three months to October, but the rise among 18 to 24-year-olds was 53,000.
Unions said the country was still suffering "mass unemployment", while business leaders voiced concern that youth unemployment was edging towards a million.
Figures from the Office for National Statistics showed private sector employment increased for the sixth consecutive quarter, by an estimated 151,000 to 24.010 million, while public sector employment fell for the 13th consecutive quarter, by 20,000 to 5.7 million, the lowest for over a decade.
Employment Minister Mark Hoban said: "It's a credit to businesses that the private sector is employing one and a quarter million more people than when this Government took office, helping us compete in the global race. Today's figures show that, against a difficult economic backdrop, we're helping people to move off benefits and into work."
Chancellor George Osborne said in his Budget speech that for every job lost in the public sector in recent years, six had been created by private firms.
But TUC general secretary Frances O'Grady said: "Today's figures confirm our fears that economic stagnation has finally caught up with the jobs market.
"Young people are bearing the brunt of our jobs crisis, with the number of unemployed youngsters up 48,000 and approaching a million again. The news for those in work is not much better, with the gap between wages and the rising cost of living getting even wider."