The statistics agency said a monthly increase in unemployment between December and January was not surprising given seasonal factors, but economists had expected the rate to rise to just 5.7 percent, according to a survey by SME Direkt.
In January, 283,000 people were out of work, the same number as in January 2005.
In total, 4,192,000 people held jobs in Sweden in December.
On Monday, Labour Minister Hans Karlsson said Sweden’s unemployment rate was likely to fall to about 4.0 percent by the summer.
The forecast echoes the ruling Social Democrats’ campaign promise before Prime Minister Göran Persson took office in 1996 to halve Sweden’s unemployment to below four percent.