At 1602 GMT, the rand traded at 17.3375 against the dollar, 0.77% weaker than its previous close.
The rand's weakness reflects domestic growth concerns due to an ongoing electricity crisis, Investec analyst Annabel Bishop said in a note.
"The looming threat of stage 8 load shedding, and outages including stage 6 so far, have eroded confidence in the domestic economic outlook, with no government solution in sight in the near-term, pushing the rand weaker," Bishop said.
This week, local investors will be looking at money supply and trade balance figures for December, as well as the purchasing managers' index survey for January by S&P Global for clues on the health of the economy.
The December budget surplus rose to 44.97 billion rand from 41.89 billion rand a year earlier, National Treasury data showed on Monday.
In the equities market, the Johannesburg All Share index dropped 0.56% to 74,343 points, while the Top-40 index closed 0.58% lower to 80,324 points.
The government's benchmark 2030 bond was weaker in afternoon deals, with the yield up 2.5 basis points to 9.690%.
(Reporting by Bhargav Acharya and Anait Miridzhanian; Editing by Savio D'Souza and Andrew Heavens)
