Khenyeza joined Usuthu at the start of last season after he was released by neighbours Lamontville Golden Arrows and he was handed a one-year deal with a one-year option to renew.
The 35-year-old scored six goals in 29 league appearances last season as Usuthu finished fifth on the NFD log, but have since bought their way into the top-flight by purchasing the status of promoted Thanda Royal Zulu.
Nomvethe, 39, who joined the club from Moroka Swallows in the January transfer window last year, showed no signs of slowing down by scoring 17 league goals in 27 league appearances.
The club were keen to hang onto the duo for their top-flight experience.
"Mabhudi and Nomvethe should be used as the benchmark to the younger players and it is why we have given them new contracts," Usuthu coach Joey Antipas tells KickOff.com.
"I definitely feel that they will be valuable to the team and they should be an inspiration to the other players."
Khenyeza and Nomvethe are the only players still playing in the PSL to have scored over 100 goals.
Meanwhile, former Bafana Bafana winger Delron Buckley, who was Antipas's assistant coach last season, is no longer part of the technical team.
Buckley joined Usuthu towards the end of 2015/16, and Antipas says he can't speak on the reasons or either dwell on why he's not part of the team.
"That one [the issue of Buckley], I wouldn't like to discuss," Antipas adds. "But I can safely say that he's not with me at training."