You need an IRD number to sell a property
Noone (including a trust and a company) has been able to sell a property without an IRD number since the brightline test came into force on 1 October 2015. Using your IRD number is not legally possible. You will have the same problem with the sale of the Trust’s home.
See here on the IRD’s website: https://www.ird.govt.nz/property/buying-and-selling-residential-property/when-you-buy-and-sell
“Land transfer tax statement
People buying, selling or transferring property must provide tax information using a Land transfer tax statement. Land information New Zealand (LINZ) collect the information on our behalf. Tax statements are required when most land is transferred.
We use the information to make sure property tax obligations are met. Even if the sale of your home is not taxable, you must provide your IRD number on the tax statement. A separate statement is required from every seller and buyer.”
In the case of a Trust, the Trust’s IRD number is required. The same requirements are detailed on the LINZ website: https://www.linz.govt.nz/land/land-registration/prepare-and-submit-your-dealing/land-transfer-tax-statements.
There are only very limited exceptions which are very rare: https://www.linz.govt.nz/kb/720
No sale can be completed until the lawyer acting on the sale receive’s the IRD number(s) of the property owner. Personal IRD numbers cannot be used if the property is owned by a company or a Trust.