The South African Revenue Service (Sars) said on Tuesday it had collected R1.2-trillion in the 2017/18 financial year ended March 31, slightly below the estimate announced in the budget in February, but up 6.3 percent from the previous year.

"The 2017/18 financial year was characterised by distinct and clearly delineated growth patterns," Sars said.

"Until December 2017, revenue in aggregate grew by 6.2 percent year on year. For the period December to February 2018, revenue growth, on a month-on-month basis accelerated to between 9.5 percent and 15.5 percent," it said.

It attributed stronger revenue growth towards the end of the financial year to an improvement in business confidence to levels last seen in 2015, resulting in improved profit outlook and hence provisional payments as well as stronger commodity prices, which buoyed company income tax from particularly the mining sector in December.

However, the slower recovery of consumer confidence resulted in lower domestic value-added tax, as more households chose to reduce debt. As a result, domestic VAT grew at a muted 4.5 percent, well below the 8.1 percent growth seen in 2016/17.

In his 2018 budget speech in February, former finance minister Malusi Gigaba said VAT would go up one percentage point to 15 percent, effective from April 1, to help boost revenue.

On Tuesday, his successor Nhlanhla Nene said the higher VAT was expected to raise an additional R22.9-billion in 2018/19. 

Revenue collected by Sars accounts for 90 percent of South Africa's budget but some of the tax department's senior officials have been implicated in graft, undermining its efforts.

"One of our focus areas should be to restore and rebuild public trust and credibility with taxpayers, traders, our stakeholders, our partners, and all South Africans," Nene said.