Berg has inked a four-year contract with the Athens club and will reportedly receive an annual salary of €400,000 ($515,000).
The 27-year-old has scored six goals in 23 appearances for the Swedish national team.
Berg is one of few Swedish stars on the move this summer, although according to the Aftonbladet Silly Season blog rumours continue to circulate around some of the country’s more established stars.
Johan Elmander, once of Bolton Wanderers and now plying his trade with Turkish heavyweights Galatasaray, has been linked with a move away from the Istanbul club.
With Didier Drogba, Burak Yilmaz and Umu Bulut also at the club, Elmander has found himself out of favour, according to Aftonbladet.
It is reported that Elmander may join striking colleague Berg in Greece with Olympiakos said to be willing to offer 15 million kronor ($4.7 million) for the 32-year-old.
A third Swedish striker, Ola Toivonen, could also be on the move after confirming last week that he is to open talks with Premier League side Norwich over a possible move from Dutch side PSV Eindhoven.
Finally superstar striker and national team captain Zlatan Ibrahimovic is rarely out of the headlines with speculation persisting that he will follow Carlo Ancelotti out of Paris Saint Germain.
Ibrahimovic has been a regular mover in his glittering career and a transfer back to Italy has been mooted.