The agency’s investigation has also led to 272 people being imprisoned for a total of 360 years, the report published on Tuesday, shows.

The government granted extra funds to the agency in 2006 earmarked for the improvement of tax controls.

So far more than 1,200 people have been charged for a range of offences.

Many of the cases of illegal labour emerge from tips and the company is thereafter investigated by the agency. Each investigation has on average netted an additional 2.7 million kronor in unpaid tax revenues.

The report shows that 75 percent of the economic crimes are committed in the Stockholm area.

The agency reveals in its report that much of the crime is connected to organized syndicates and is focused in several key industries such as construction.

The agency learned however that organized black markets in labour are also prevalent in other sectors such as transport, hotel and catering and cleaning.

To assist the investigation the agency put together a centralized analysis group (URAN) to develop a more systematic operation into the black market in labour.

The agency’s work to combat illegal labour will continue in a new project that will run until December 31st 2012.