A wealth tax, an increase in personal income tax and hikes in corporate tax . none of these are considered options for Tito Mboweni, who presents his first budget as finance minister on February 20.
Adding to the challenging environment are the May 8 general elections and that the government may try to appease rather than alienate voters ahead of the polls.
At most the National Treasury is expected to boost the collection of personal income tax - without announcing a tax increase - through the effect of bracket creep. This is when inflation pushes pay packets into higher tax brackets and the government does not fully adjust tax brackets to compensate.
Economists say allowing for bracket creep can add an additional R10bn-R13bn in personal income-tax collection, which is one of the four largest tax mechanisms for the government.
A further VAT increase, following a one-percentage-point hike to 15% in April last year, is unlikely, even though SA's VAT rate remains low on a global comparison.
Sanisha Packirisamy, an economist at Momentum Investments, said the government's aim to increase investment suggested that the corporate tax rate, which at 28% is relatively high on a global scale, would remain unchanged.
A carbon tax bill was tabled in parliament on November 20 2018 and is expected to be implemented in June. It affects any partnership, trust, community, municipal entity or publicly listed entity whose activities cause the emission of greenhouse gases above a threshold.
As of December 31 2022, the carbon tax, now at R120/t, will rise at a rate of inflation plus 2% each year.
Sin taxes will rise but these, along with the sugar tax that was introduced last year, are not sufficient to fill government coffers.
As Maarten Ackerman, chief economist at Citadel, said: "We need to increase something like VAT or personal income tax to move the needle."
But SA's tax regime is thought to have reached the portion of the Laffer curve - a theoretical relationship between tax rates and the resultant government revenue - where higher tax rates are unlikely to result in more revenue.
This concern has been raised previously by Mboweni.
"They won't get the result they are looking for by doing that, so we're very close to a 'tax revolt'," Ackerman said.
"We do know that high-income earners are already looking at ways to reduce their tax burden."
This is taking place through financial migration or investing in different structures.
Research indicates that the high-income bracket in SA, comprising the top 1%-2% of earners, who account for 25%-35% of tax revenues, is shrinking.
Ackerman said this was also due to people "trying to rethink how they earn money", in addition to the emigration of high earners.
People could also find different ways to do the same job and earn the same money as opposed to earning a salary that directly puts them in the maximum PAYE bracket, he said.
Raising the capital gains tax or implementing a wealth tax was also out of the question in the current environment, he said, because people might delay the activities that could trigger a capital gain.
Problematic state-owned enterprises may be another highlight of the budget.
Packirisamy said the government had previously noted that additional finance for failing SOEs would have to be done in a deficit-neutral manner.
"Additional announcements may be made in relation to the SABC, which has requested a R3bn bailout to prevent retrenching workers, and SAA, which requires R9.2bn to repay its debt, maturing in March 2019."
In a report, Deloitte said that in the current climate "it is hard to see how the National Treasury will be able to prioritise the National Health Insurance scheme, despite the years of planning and political will which have gone into this initiative".
And this week protests at universities highlighted one of the many challenges the government faces to ensure that more South Africans were absorbed into the economy. Last year Jacob Zuma, while still president, committed the government to funding tertiary education for students with a household income of R350,000 or less, costing the fiscus R57bn.
Delia Ndlovu, MD for Africa tax and legal at Deloitte, said this was "a decision which will continue to impact this year's budget despite concerns that this is not sustainable".
The professional services advisory firm expects further clarity on aspects of VAT regulations, such as the treatment of educational services, electronic services and VAT deductions, and cryptocurrency.
But there could be a silver lining.
In October, the finance minister indicated the budget deficit might rise to 4% of GDP and debt to 60% of GDP.
However, government financial statements for the nine months of the current fiscal year show the state has been trying to cut back on spending through cuts to entertainment and limits on salary hikes.
This may improve the deficit to 3%, though the debt-to-GDP ratio may remain high as the state may look to additional borrowing rather than increasing taxes.
However, Ackerman said: "That government did start cutting back on expenditure . puts things in a position where, compared to this time last year, we don't necessarily need to increase taxes right now to make the budget balance."
A key focus for the National Treasury is rebuilding the SA Revenue Service (Sars). This week a panel was appointed to select the new Sars commissioner. It includes former finance minister Trevor Manuel, Thandi Orleyn, an advocate, and Ismail Momoniat, deputy director-general for tax and financial-sector policy at the Treasury.
In the Deloitte report, Ndlovu said since raising taxes would be difficult, one way of bringing in additional revenue was by increasing collections and building capacity at Sars. "We expect this will be a priority, as the medium-term budget policy statement already allocated R1.4bn to this in October."..