Spanish second division clubs Las Palmas and Rayo Vallecano, plus seven professional footballers, are to be investigated over betting on matches.
The Spanish Football Federation (RFEF) will conduct the inquiry after a tip-off from European governing body Uefa.
Las Palmas listed the names of the players - none of whom are in their squad - in a statement on its website.
In November, Uefa named five clubs that it wanted to investigate following allegations of match-fixing.
The clubs are KF Tirana and KS Vllaznia of Albania, FC Dinaburg of Latvia, NK IB Ljubljana of Slovenia and Budapest Honved of Hungary.
The five were involved in seven games, one Champions League qualifier and six Europa League qualifiers, between 16 July and 6 August 2009.
No matches involving British clubs are under scrutiny.
The seven games have been whittled down from the 40 that Uefa said in September it was investigating.
European football's governing body is also looking into the roles of three referees and one other official.
Also last month, German prosecutors revealed they were probing possible match-fixing at about 200 games, which included Uefa's original 40, played in Germany, Belgium, Switzerland, Croatia, Slovenia, Turkey, Hungary, Bosnia-Herzegovina and Austria.
Thirty-two matches in Germany are under suspicion.
Uefa has met with the national football associations of Austria, Belgium, Bosnia and Herzegovina, Croatia, Hungary, Slovenia, Switzerland and Turkey to discuss the matches under investigation.
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