Canoe Racing NZ said it would not be providing further details of the allegations at the moment "out of consideration for the privacy of the complainants".
Thompson's membership has since been suspended pending an outcome of the independent investigations.
Thompson has denied that either incident occurred, according to the statement.
A statement provided by Thompson's lawyer to Stuff, David Fraundorfer, said Thompson denied the allegations "in the strongest terms".
In that statement Thompson was said to be "distressed that CRNZ has placed matters in the public domain before complaints have been fully determined".
Casey's investigation found that the alleged conduct occurred and that it was "unbecoming of a CRNZ member and contrary to CRNZ's goals".
Following the investigation, the Canoe Racing NZ board resolved to expel Thompson.
"The CRNZ Constitution sets out that a member may be expelled only by Special Resolution of Members at General Meeting."
The meeting is scheduled for December 22.
The Canoe Racing NZ Board said the "welfare and confidentiality" of the complainants is of the highest priority.
"As is continuing our commitment to ensuring a culture where inappropriate behaviour can be addressed in a secure and confidential manner and the appropriate process can be followed."
Thompson won a two gold medal at the 1984 Los Angeles Olympic Games for the K1 1000m and K2 500m.