At 1300 GMT, the rand traded at 18.625 against the dollar, about 0.16% stronger than its previous close, having initially strengthened around 0.3%.

The dollar last traded around 0.37% stronger against a basket of global currencies.

Finance Minister Enoch Godongwana announced that revenue collections in the current 2023/24 fiscal year were below estimates in the main February budget.

The Treasury said it remained committed to stabilising public finances through spending cuts and unspecified tax revenue measures, as well as a reconfiguration of government that would involve the merging or closure of state-owned entities (SOEs).

"The positive response by the ZAR is perhaps a sign of approval pertaining to the suggested fiscal discipline and no news of further allocations to ailing SOEs," said Shaun Murison, a senior market analyst at IG.

Major constraints on South Africa's economic growth in the past decade have been rolling power cuts, as utility Eskom struggles with breakdowns of its ageing coal plants, and underperformance at state-owned logistics company Transnet.

International investors responded positively to the budget, after the government's sovereign dollar bonds fell as much as 0.6 cent earlier in the day.

Longer-dated notes rose the most, with the 2052 maturity up 0.544 cents on the dollar to 78.24 cents at 1330 GMT.

"The main positive is that there is no additional (bond) issuance over and above what was already factored in," Nick Eisinger, co-head emerging markets active fixed income at Vanguard, said. "That has seen the bonds rally a bit."

On the Johannesburg Stock Exchange, the blue-chip Top-40 index traded around 0.03% weaker.

South Africa's benchmark 2030 government bond was stronger, with the yield down 9 basis points to 10.585%.

(Reporting by Tannur Anders and Rachel Savage; Additional reporting by Marc Jones in London; Editing by Nellie Peyton, Angus MacSwan and Shounak Dasgupta)