FIFA's disciplinary committee held the Equatoguinean FA (Feguifut) liable for the use of a "forged or falsified" passport during last year's qualifying tournament for the Rio Olympics.
Football's world governing body said it had found evidence of the use of two passports with different dates of birth for Camila Maria do Carmo Nobre de Oliveira, who took part in several qualifying matches.
"Two birth certificates containing divergent information regarding the player’s parental affiliation were also provided," FIFA said.
The player was banned for the next 10 international matches for which she would be eligible, fined 2,000 Swiss francs ($2,100), warned and reprimanded. Feguifut was fined 40,000 Swiss francs.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"Further investigations related to the eligibility of several other players are currently ongoing," said FIFA.
Equatorial Guinea did not qualify for the women's football tournament after losing to South Africa in the final round, having previously beaten Congo and Nigeria two-legged matches.
The West African nation's men's team were kicked out of the 2015 African Nations Cup for fielding a Cameroon-born player who was not eligible to represent them in qualifying matches.
Equatorial Guinea were later given a place in the tournament when they agreed to step in as hosts after Morocco withdrew.
(Writing by Brian Homewood, editing by Ed Osmond)
