In March, the FIS had banned athletes from Russia and Belarus until the end of the 2021-22 season but that suspension has now been extended into next campaign.
Several sporting bodies had banned athletes from both countries after the invasion, which Moscow describes as a "special military operation".
Belarus has been a key staging area for Russia's invasion of Ukraine.
"The FIS Council decided, with due regard to the integrity of FIS competitions and for the safety of all participants... to continue its policy to not allow Russian and Belarusian teams and athletes, to participate in all FIS competitions," it said in a statement.
The FIS said the decision was in line with recommendations made by the International Olympic Committee (IOC).
The IOC's executive board had recommended in February that sports federations ban Russian and Belarusian athletes and officials from competing in events following the invasion.