TOKYO: Toshiba's president Nobuaki Kurumatani will resign on Wednesday, reports said, as a buyout offer from a private equity firm stirs turmoil inside the Japanese firm.

Kurumatani is expected to offer his resignation at a board meeting later in the day, according to the Nikkei, a leading business daily, and other Japanese media, citing unnamed sources.

In a statement, Toshiba confirmed only that its board of directors would meet Wednesday "and is scheduled to discuss the appointment of representative executive officers".

The reported resignation comes as board members raise questions about a buyout offer from CVC Capital Partners, where Kurumatani formerly headed Japanese operations.

CVC's buyout offer is said to be in excess of $20 billion, but reports suggest that figure is seen by some in Toshiba as too small.

The resignation reports came as the Financial Times said another private equity fund, KKR, is planning to offer its own larger buyout proposal, setting off a potential bidding war.

Bloomberg News said a third fund, Canadian Brookfield Asset Management, was also exploring a possible offer.

Kurumatani will reportedly be replaced by chairman Satoshi Tsunakawa.

Toshiba last week confirmed it had received an offer from CVC Capital Partners, which would take Toshiba private and potentially shield it from activist shareholders.

The firms have close ties, with Kurumatani working for CVC between 2017 and 2018, and a senior executive at CVC Japan currently serving as an outside director on Toshiba's board.

The turmoil inside Toshiba is likely to be a fresh blow for the Japanese household name, which has been trying to improve its governance after an accounting scandal in 2015 and the 2017 bankruptcy of its US nuclear plant subsidiary.

After sweeping restructuring, its earnings rebounded and it returned to the prestigious first section of the Tokyo Stock Exchange in January.

Any buyout offer for Toshiba is likely to face significant challenges, including securing financing and regulatory approval.