Up to 2.4 million superannuation members could be impacted by the allegations which have rocked insurance company CommInsure, according to Rainmaker Information estimates.
A joint investigation by Fairfax the ABC's 4 Corners alleged the company pressured doctors into changing their assessments of customers to avoid payouts, delayed payouts to terminally ill customers and refused to honour claims to former staff who were medically retired.
Rainmaker said that while not all of the members of funds using the insurer will have a policy, up to 2.4 million superannuation members could hold TPD or income protection insurance through their funds. The researcher estimates CommInsure has a roughly 20% share of the group insurance market.
CommInsure clients NGS Super and CareSuper have publically signalled they are reviewing their relationship with the insurer in the wake of unethical practices exposed in the media.
CareSuper chief executive Julie Lander said she was "deeply concerned" and "disappointed" by the allegations: "At CareSuper, we have always been committed to working with organisations who share our values and our dedication to members. We have members' best interests at the core of everything that we do.
"As with any contractual arrangement, we undertake a regular review of our insurance to ensure that the product offer meets our members' needs."
CareSuper commenced its review of CommInsure late last year with the current contract due to expire at the end of 2016. The review will be finalised by July.
A statement posted on NGS Super's website said the fund is currently in the midst of an insurance review with CommInsure.
"As part of this review, NGS will take into consideration the ethical standards and governance approach of CommInsure," the fund said. "We apply these standards across any review process as a matter of principle, and if any of our business partners do not meet these standards, this may trigger a new partner tender."
Plan For Life numbers for 12 months to 30 June 2015 show that CommInsure's share of the overall insurance market, both group and non-super, was already declining before the allegations came to light. CommInsure's market share progressively fell from 13.1% to 12.1% over the previous three years.
A previous version of this article incorrectly stated that HOSTPLUS and AMIST currently use CommInsure for its group insurance. Financial Standard apologises for the error.