The former Stevenage centre-back, who joined Guy Whittingham's side on a one-month deal at the beginning of the season, will remain at Fratton Park until January.
Portsmouth boss Guy Whittingham has been very impressed with N'Gala.
He told the club's official website: "Bondz has been excellent. He puts his body on the line all the time to get in front of shots.
"He knows when he needs to work hard on the training ground and we have been very impressed."