Faltskog, who has come out of retirement to release a solo album called "A", was asked by German's Die Zeit Magazine if she would be open to an ABBA reunion and she responded positively.
"Maybe a charity concert? I would not say 'No' right away," she said.
Her former husband Bjorn Ulvaeus and his fellow ABBA songwriter Benny Andersson vowed in 2008 not to reform the group that broke up in 1982 after nine British No.1 hits.
The fourth member of the group whose hits included "Mamma Mia", "Super Trouper", and "Dancing Queen", was Anni-Frid Lyngstad.
But speculation about ABBA reforming has mounted in the lead-up to the opening of a ABBA museum in Stockholm in May.
British bookmakers Paddy Power seized on the speculation to offer odds of 14/1 for ABBA to perform together in 2013.
The bookmaker was offering 16/1 on ABBA opening the 2013 Eurovision Song Contest in Malmo, Sweden, on May 16 as this was the show that propelled ABBA to fame following their 1974 win with the song "Waterloo".
"ABBA fans will be spitting out their meatballs in excitement at prospect of a reunion. Given home turf, plus the 40th anniversary of their Eurovision triumph, Paddy Power's 16/1 to open the show looks to be worth a pound of anybody's money," said a spokesman for the bookmaker.
(Reporting by Belinda Goldsmith, editing by Paul Casciato)