The Serious Fraud Office raided the offices of a trust aligned with Kīng Tūheitia as part of an ongoing investigation.

A Serious Fraud Office (SFO) spokesperson confirmed a search warrant related to an investigation concerning the Ururangi Trust was executed on Tuesday morning.

It's understood the trust is under investigation for spending that may have contravened its status as a charitable organisation.

The trust voluntarily deregistered from the Charities Register, effective as of June 1 this year.