Former Ajax Cape Town midfielder Siwahla was last at FC Cape Town, while Mashego is looking for a club after being deemed surplus to requirements at Orlando Pirates.
"He [Siwahla] is training with us, but I'm not going to say if he'll sign for the club," Chippa coach Roger Sikhakhane tells KickOff.com.
"We have a few players that we have invited to come and train with us. We are going to give them two weeks then after that we'll make a decision if we are going to sign them or not."
Chippa have found the going tough in the PSL, failing to record a win in their first four games.
They led 1-0 against Bidvest Wits yesterday before Erwin Isaacs netted an 89th-minute equaliser.