Tembo's future at United has been the subject of speculation in recent months but the club boss has assured the former Zimbabwe international defender that he must not worry about his future.
"Kaitano has a two-year extension clause in his contract. There is no question in our minds that he deserves an extension whatever happens," Matthews says.
"He won us a trophy and we are sitting okay in the league. He brought through three young players. He is a club man.
"I am not sure where this media nonsense comes from around his contract. Kaitano's job is not under threat. He will be with us next season no matter what."
Tembo won the MTN8 trophy with SuperSport earlier this season and has secured some big results against the top teams.