SA Rugby has attempted to halt the overseas exodus by ruling that only internationals with a minimum of 30 caps will be be able to play abroad and represent the Springboks.
Concerns over the number of players plying their trade outside of their homeland have long since been expressed.
The governing body on Friday announced a new measure which will be implemented after the three-match series in France in June, but players with any number of caps will be available for selection during a World Cup year.
"We are sending a message to young players that if they wish to play for the Springboks, then they must remain in South Africa,” said SA Rugby president Mark Alexander.
"But we have also retained flexibility for the coach to select exceptional players who may be based overseas provided they have a proven track record of 30 Tests for the Springboks.
"How to balance the need to select the strongest possible team against the challenges of having such a large number of players based overseas has been a subject of long debate in our game.
"We have made this change in what we believe are the best interests of the Springbok team but we will review it periodically in conjunction with the national coach."
Such measures are becoming increasingly commonplace in world rugby, with Australia, England, Wales and New Zealand all limiting selection of foreign-based players.