The former Orlando Pirates and Mamelodi Sundowns midfielder was training with the Lions of the North with the hope of getting a contract, but came up short.
Da Gama is led to believe Mokoena has since linked up with National First Division side Maccabi FC.
"We have not signed Mokoena. I think he is training with Maccabi FC," Da Gama said.
"We thought against that because we really feel we should reinforce the defence. We also need to reinforce the midfield and strikers. So yes, definitely there are opportunities for us. We are going to strengthen the team, there is no doubt about that. We are definitely going to strengthen with top quality players, you can believe me."
Meanwhile, Da Gama was disappointed to see his men surrender a 2-0 lead in a 2-2 draw with fellow promoted side Black Leopards at Makhulong Stadium on Thursday.
"What I was disappointed about was the leadership on the field. We played football at the highest level and coached at a high level. With five minutes to go it was very poor leadership for me on the day. We won't single out or blame anybody, we take it as a team. For us this is a loss."