Rain halted the CSA One-Day Cup match between the NWU Dragons and the DP World Lions at the JB Marks Oval on Wednesday.
The Lions, who were asked to bat first by the hosts, were on 229-3 after 42 overs when the contest was interrupted.
Hamza was leading the charge for the Lions with an outstanding unbeaten 115 runs from 121 balls.
This is his 21st List A century. The 30-year-old reached the milestone in the company of Wiaan Mulder (50*), with whom he shared an unbroken 111-run fourth-wicket partnership.
The pair got together after Mitch van Buuren's dismissal in the 22nd over and looked comfortable until the rain interruption.
Mulder, for his part, had worked his way to a 15th List A half-century off 63 deliveries.
Hamza’s 77-run second-wicket partnership with Rassie van der Dussen was the Lions’ second-highest in the innings.
Caleb Seleka was the pick of the bowlers for the Dragons at the time of the interruption.
He had a single wicket for 46 runs in eight overs. Onke Nyaku and Dian Forrester also had a wicket each but had higher economy rates.
DRAGONS: Meeka-eel Prince (wk), Wihan Lubbe (capt), Dominic Hendricks, Rubin Hermann, Dian Forrester, Ruan de Swardt, Paul James, Onke Nyaku, Migael Pretorius, Caleb Seleka.
LIONS: Reeza Hendricks, Zubayr Hamza, Rassie van der Dussen, Mitch van Buuren, Wiaan Mulder, Connor Esterhuizen (wk), Bjorn Fortuin (capt), Codi Yusuf, Nqaba Peter, Lutho Sipamla.