Mabena, 33, has become their attacking talisman since his arrival from the now-defunct Platinum Stars in July 2017 and has emerged as one of the leading attackers in the DStv Premiership.
With 25 goals and 15 assists in 107 games for Siwelele, Mabena's long-term future was subject to debate as his contract was due to expire at the end of next season.
Celtic's high publicised financial issues raised further doubt that he'd extend his stay but the club has since announced they have tied him down until the end of the 2023/24 campaign.
"Bloemfontein Celtic is delighted to announce that Ndumiso Mabena has extended his stay at the club until June 2024. The journey continues," the club statement read.
Mabena joins goalkeeper Jackson Mabokgwane who signed a long-term contract last week as they look to retain an experienced core to build a new youthful side around under head coach and club legend John Maduka.