The pair will add experience to the squad for rookie coach Kurt Lentjies as the side look to move up the table in the second half of the season.
Both players were part of the sale of Bloemfontein Celtic to Royal AM, but have been used sparingly this season.
Luthuli made a single substitute appearance against Stellenbosch FC in November, while Pfumbidzai has not featured at all. In fact, his last game was in March 2021 before injury struck.
“The players have been selected for their quality and consistency in all aspects of the game,” Chippa said in a statement. “Their capabilities and potential with their erstwhile teams, including the now-defunct Bloemfontein Celtic, are a key factor and we trust that they will thrive in the Chippa United FC environment.”
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Chippa hinted there could be more arrivals too before the transfer window closes on Monday.
“Further announcements concerning the current transfer season will follow in due course,” the statement said.