Gaxa, who joined Amakhosi from SK Lierse this month, would become the 19th South African to reach the milestone in 20 years of Bafana Bafana football.
It has taken the defender seven years to approach the half-century mark. Sundowns playmaker Teko Modise is the quickest player to 50 Bafana caps, taking just short of three years.
Gaxa will, however, have to usurp first-choice right-back Anele Ngcongca at the weekend.
Meanwhile, Moroka Swallows striker Siyabonga Nomvethe is expected to pass Benni McCarthy to become the country's second most-capped player. The veteran hitmen, both 34, are tied on 79 international appearances.
Former national captain Aaron Mokoena is Bafana's most experienced campaigner with 107 caps.