Kevin Lampen-Smith, Real Estate Agents Authority chief executive, said on December 11 that his organisation was working with Preet & Co and Harcourts as a result of its investigations.
"We are confident no consumers have lost funds as a result of the abnormalities in this trust fund. As our investigations are ongoing we are unable to comment further," he said.
Grewal, a licensed agent who is managing director of the multi-agency Harcourts Preet and Co Group, said las month that he found a discrepancy in the trust account funds and notified the auditors and Harcourts.
"No funds were ever transferred to me. No one has suffered any loss and I have stepped down while the Real Estate Agents Authority investigates as that is the appropriate thing to do," Grewal told the Herald in early December.
Agents operate big trust accounts where client money is deposited while property buys are completed and those accounts must be audited. Rental money is often deposited with property management businesses by tenants before landlords are paid.
In 2016, Grewal said Harcourts Preet & Co had the Manukau, Otahuhu, Botany and Ellerslie offices, and had also taken over the established Harcourts offices in Howick, Meadowlands and Pakuranga.
Grewal's website said the group had "overseen the complete transformation of this real estate firm into one of the leading agencies in South and East Auckland.
Harcourts chief executive Chris Kennedy confirmed last month that Grewal had stepped down.
"[He] has voluntarily suspended his licence while the REAA looks into possible abnormalities in the trust account for Preet & Co Real Estate. However Harcourts Group Ltd has ensured no member of the public with monies in the trust account has been affected.
"Preet Grewal is a shareholder in Preet & Co Real Estate Ltd and Preet & Co Rentals Ltd with 10 offices and he is still on the company's web site," Kennedy said.
The REAA shows Grewal first entered the register of licensed salespeople in 2009.
Comment has been sought from Harcourts and the authority on the situation.