Defending champion Panathinaikos kicks off the Greek league season against Xanthi on Friday, with two new French signings joining star striker Djibril Cisse in the squad.
Defender Jean-Alain Boumsong and forward Sidney Govou both signed in the summer from Lyon to boost Nikos Nioplias' squad ahead of the new season.
Fellow France international Cisse scored 23 goals last season to lead Panathinaikos to its first league title in six years.
Rival Olympiakos, which had won the championship each of the previous five years, was six points adrift and its preparations for the new season have been far from perfect.
An embarrassing exit from the Europa League at the hands of Maccabi Tel Aviv led to the sacking of German coach Ewald Lienen after just 52 days at the helm, with Ernesto Valverde returning to the club he led to the domestic double in 2009.
However, Olympiakos has been strengthened by the signing of Spanish winger Albert Riera for a reported ?20 million ($26 million) from Liverpool, and Villarreal striker David Fuster is poised to join him by the end of the week.
''I agreed to join Olympiakos only because Valverde is the coach,'' Fuster told reporters. ''It doesn't matter that we will not play in any European tournament. We'll fight for both Greek titles, the league and the Greek Cup.''
Olympiakos, which begins the season at Iraklis on Saturday, also looks set to beat Panathinaikos to the loan signing of Liverpool's Hungarian striker Krisztian Nemeth.
PAOK Thessaloniki and AEK Athens, who are also expected to be title contenders this season, both open against newly-promoted sides on Sunday.
PAOK hosts Panseriakos, while AEK travels to the island of Corfu to face Kerkyra, which has returned to the top division for only the second time in its 41-year history.
Dusan Bajevic has kept his job as AEK coach despite the opposition of a group of hardcore fans of the club, who recently attacked and slightly injured Bajevic at the end of a friendly game.
