The Urban Warriors announced the news on their official Twitter page on Friday, two days after the January transfer window deadline.
The 33-year-old right-back joins on a free transfer after he was released by Absa Premiership champions Bidvest Wits at the end of last season.
“I’m delighted to have joined Ajax Cape Town and I am really grateful to head coach Muhsin [Ertugral] and the management for the opportunity to play football again,” Gaxa told the club's website.
“I am well aware of the situation the club finds itself in at the moment and I just want to help with my experience.
"I’ve played professionally for well over a decade and I believe I can contribute on and off the field in assisting this club move up the log standings."
The former Kaizer Chiefs fullback had been training with the Cape-based outfit since the start of January, and has been rewarded for his persistence to earn his way back into professional football.
“What I have seen here [at Ikamva], the talent is amazing, the club structure is something that has really impressed me and I am grateful to be part of this unique institution.
“I am really grateful to Mushin for showing faith in me and I can’t wait to start my journey here,” he concluded.