Every government tender requires proof of tax compliance. SARS replaced the old paper Tax Clearance Certificate with the Tax Compliance Status (TCS) system some years ago, and a surprising number of bidders still submit outdated documentation, or a PIN that has since lapsed, without realising it.
The current system issues a Tax Compliance Status PIN via SARS eFiling, which a procuring department verifies directly and electronically — you provide the PIN, not a printed certificate. A tender submission still referencing an old-format "tax clearance certificate" is usually still accepted with a valid PIN, but the PIN itself is what actually gets checked.
Your Tax Compliance Status can change from compliant to non-compliant automatically the moment any return is late or any amount is outstanding — including a small, disputed, or already-being-resolved amount. A business can be tax compliant on the day they check their status and non-compliant a week later through no new action of their own, which is why this is one of the more frequent last-minute disqualification causes on otherwise strong bids.
Check your own tender qualification