The managing director and chairman of IOOF Holdings have stepped aside following moves by the prudential regulator to disqualify the beleaguered wealth manager’s top brass.

IOOF says the managing director, Christopher Kelaher, and chairman, George Venardos, have taken leave with immediate effect to focus on fighting the Australian Prudential Regulation Authority’s accusation they failed to act in their members’ interests.

They have been replaced on an interim basis by wealth management boss Renato Mota and non-executive director Allan Griffiths.

The other three people Apra is seeking to have disqualified from being pension fund trustees – chief financial officer David Coulter, company secretary Paul Vine and general counsel Gary Riordan – stay on but have relinquished any relevant responsibilities.

The move failed to halt the sell-off of IOOF shares, which fell 35.8% on Friday and were 7% lower again by close on Monday.

Apra said last week it has had concerns about conflicts of interest at IOOF since 2015, and the firm had failed to address them.

On Monday IOOF strongly denied the accusations.

“We maintain our position that the allegations made by Apra are misconceived, and will be vigorously defended,” Griffiths said.

He said IOOF acknowledged the seriousness of the allegations and that he and Mota would cooperate with Apra on what he called “previously agreed initiatives”, many of which he said were complete.

“We have a responsibility to our superannuation members, shareholders, advisers, employees and the wider community, to take decisive action.

“We are entirely focused on addressing the governance issues in the interests of all stakeholders and will do so in an orderly manner.”

Apra is also seeking to impose additional conditions on the firm.

IOOF shares were worth $4.24 at 1200 AEDT on Monday, down 64% since hitting an all-time high of $11.84 in October 2017.

The move could threaten to derail IOOF’s $975m purchase of ANZ’s financial planning businesses.

In October 2017 IOOF agreed to buy ANZ’s Australian superannuation business and some financial planning operations for $975m, but ANZ said on Friday it was urgently seeking clarification over Apra’s intervention.