The 23-year-old has yet to return to top-level competition.
"The SEGAS executive board met today and decided to suspend the benefits of the athlete Voula Papachristou from 01/04/2013 because of improper preparation and abstinence from competing," said SEGAS in a statement.
"The suspension will last until the athlete joins up with a coach who will have the approval of the federation and will resume high-level competition."
Her tweets mocked African immigrants and expressed support for a far-right party.
Speaking to Reuters earlier this year, Papachristou said she was planning to take some time out in order to get over the controversy and get in top shape for the outdoor season.
The athlete, a popular figure in Greece, is the national champion and was picked out as one of five athletes in the team to front an advertising campaign during the build-up to the London Olympics.
She was pulled from the team by the Hellenic Olympic Committee who said her comment on Twitter was against the Olympic spirit.
Papachristou later apologised for the "unfortunate and tasteless joke" which she said did not reflect her beliefs.