At 1420 GMT, the rand was trading at 15.4525 against the dollar, 2.06% weaker than its close on Friday.
The United States and its allies on Saturday moved to block certain Russian banks' access to the SWIFT international payment system, which traders and analysts said could disrupt Russian exports of all commodities from oil and metals to grains.
President Vladimir Putin meanwhile put Russia's nuclear deterrent on high alert on Sunday.
The biggest assault on a European state since World War Two, and fears it could escalate further, eclipsed any impact from local economic data released on Monday.
News from the National Treasury that South Africa's budget deficit had narrowed in January could not stem the currency's decline, with the rand always led by global factors.
The country's revenue service also reported that South Africa's trade surplus dropped in December.
Government bonds weakened, with the yield on the benchmark 2030 paper rising 14.5 basis points to 9.410%.
Shares on the Johannesburg Stock Exchange soared on Monday, driven by the collective mining and resources stocks as fears around a possible prolonged Russia-Ukraine war stoked supply concerns and increased prices of various commodities.
Palladium prices jumped by over 7% on concerns on the impact of Western sanctions on Russia, which houses Norilsk Nickel, the biggest palladium producer globally. Gold was on course to post its best monthly performance in the last nine months with the price touching $1,911 per ounce. [GOL/]
Crude oil prices continued to stay above the $100 per barrel range.
This led to a rally in resources stocks with the JSE's resources index posting a jump of 6.29% and major gold and platinum group metal (PGM) miners posting sharp gains of around 10% on the day.
The FTSE/JSE benchmark all-share index ended up 2.54% at 76,091 points and the blue-chip index of top 40 companies closed up 2.81% at 69,624 points.
(Reporting by Olivia Kumwenda-Mtambo and Promit Mukherjee; editing by Uttaresh.V and Nick Macfie)
