South African officials said in December that they remained "fully committed" to hosting the event despite falling short of requirements.
Durban was awarded the Games in 2015 after being the only city to make a confirmed bid. Edmonton, Canada had withdrawn from the running, citing falling oil prices.
"I don't want to raise your expectations and say everything looks good, it doesn't because we don't agree on the fundamentals and that is the operational budget," Mbalula told a media briefing.
