2 November 1997, Sørlie Lybekk debuted in a friendly against Germany, marking the beginning of a long career for the Norwegian side. She participated in consecutive international championships from her debut in the 1998 European Championships until the 2008 Olympics, except for the 2004 European Championships where she was dropped after having suffered injuries preventing her from a necessary build-up, and the World Championships the following year. At the 2004 European championship she was not included in the main team, but was listed as home reserve. When Isabel Blanco injured her thumb during the championship, Sørlie Lybekk was called to join the team, and received a gold medal from the championship without playing. Before the 2000 Olympics, she was named vice-captain for Kjersti Grini, and when Grini withdrew from the 2000 European Championships she captained her national team at the age of 22 at a difficult moment when many experienced players had recently retired. She remained in this position until the 2003 World Championship where Gro Hammerseng took over the captaincy. The tournament was disappointing for both the squad and Sørlie Lybekk, as they finished 6th in the tournament keeping them out of the Olympic tournament the following year.