Mhlongo, who was on loan at Chippa United last season, was rumoured to be on City's radar.
Comitis, however, says there is no substance to such talk.
"There is no truth in that rumour," says Comitis.
City are looking at recruiting towering keeper Velic. The 23-year-old previously worked with club coach Benni McCarthy at Belgian outfit Sint-Truidense, and currently plies his trade at FK Mladost Doboj-Kakanj in Bosnia-Herzegovina.
"We have shown interest to sign a keeper," Comitis adds.
"We are looking at options. We are looking at a player overseas that Benni recommended. He worked with him in Belgium.
"We are definitely looking at strengthening that department, but we have not made a decision yet."
Meanwhile, the Absa Premiership side have parted ways with defensive duo Tshepo Gumede and Vincent Kobola.