If you have an Extension of Time (EOT), terminal tax is due 7 April the following year. For example, terminal tax for the year ended 31 March 2020 is due 7 April 2021.
If you don’t have an extension of time, then this payment will be due by 7 February the next year.
* you'll be automatically granted the EOT when linked to a tax agent (such as Beany). However, if you are consistently late filing income tax returns and/or not paying your tax on time, the IRD may withdraw the EOT, even if you're still with a tax agent.