The quality of audits is improving but a review by the Financial Markets Authority shows some mixed results.
The FMA looked at the quality of 20 audits, more than half for companies listed on the stock exchange.
The survey showed were fewer problems in each individual audit compared with last year's survey but the number of audits that did not comply with standards was unchanged.
Capital Markets director Sarah Vrede said about a third of reports were found to be non-compliant.
"Thirty-five percent might sound quite high but we select files that we believe are more likely to reveal issues and that's so we can continue to give signals back to the audit sector about how they can improve.
"It's also worth pointing out that a non-compliant ratting doesn't mean that the financial statements didn't show a true fair view or required re-statement.
She said "non-compliant" simply meant the audit file did not meet all the auditing standards in every regard.
"Where we do come across something we believe means the financial statements are not showing a true and fair view or require a re-statement, we will request re-statement."
Vrede said auditor independence should continue to be a focus for auditors and directors of firms, but said no serious issues with independence were identified.
"This year we have fewer findings relating to auditor independence. The FMA's view though is that auditor independence is really critical to investor confidence."
"It can affect perceptions about quality as much as actual quality.
She said auditors would need to be "on their game" when it came to auditing reports and the impacts of Covid-19.
"Next year we're going to be focused on a number of Covid-related risks and issues, so going concern, the valuation of non-financial assets... and we would be looking for additional disclosures [regarding Covid-19]."