Reports in the UK Guardian daily also note the Swedish government's relative silence on the matter.
Swedish, German, French and Spanish intelligence services have conducted a close cooperation with GCHQ over the past five years, developing methods for the mass surveillance of data and telecom networks, The Guardian wrote on Friday.
The conclusions were based on documents provided by the US whistle blower Edward Snowden who remains in temporary asylum in Russia.
The surveillance is mostly conducted by the direct tapping of fibre optic cables and the development of "secret relationships" with telecommunications companies, the newspaper wrote, without further specification.
Snowden's documents show that GCHQ played a leading role in providing advice to the European partners to get around legislation that limits opportunities for surveillance.
GCHQ is reported to be have been delighted when Sweden's Riksdag in 2008 clubbed through the law that gives the National Defence Radio Establishment (FRA ) the right to monitor traffic in fibre optic cables. The British intelligence agency furthermore is reported to have taken some credit for the success of having provided advice and guidance to the Swedes.
"We are prepared to assist FRA further when they have developed a plan to take the work forward."
The Local reported in October that British investigative journalist Duncan Campbell has claimed that Sweden collaborated with the USA on the internet monitoring FRA law and that the country is on the same level of surveillance as Israel.
Campbell made the claims in an interview with the Dagens Nyheter daily which followed his revelations in September that Sweden is one of America's key partners in efforts to monitor internet communications across the globe.
"When you put together the pieces of the puzzle it becomes clear that Sweden worked together with the US and the UK in order to create new laws for mass surveillance online," Campbell told the newspaper.
The Guardian has furthermore concluded that while the German, French and Spanish governments have reacted angrily to the US intelligence body the NSA , which is reported to have monitored millions of citizens of these countries, while Sweden has so far been relatively quiet.