The group that inclues Bain Capital and SK Hynix has raised its offer for Toshiba's chip business to 2.4 trillion yen ($22.3 billion) including a 200 billion yen investment in infrastructure, "sources familiar with the matter" told Reuters.

The offer by the consortium, which is led by the U.S. private equity group and the South Korean chipmaker as well as Japanese state-backed investors, was higher than an initial offer, according to the report.

Toshiba declined to comment on details of the deal negotiations.

The move comes after sources said Western Digital which was part of a competing group in final-stage talks with Toshiba, had revised its offer.

Toshiba is desperate to sell the unit and cover billions of liabilities at its U.S. nuclear unit Westinghouse. Last week it said it was considering three competing offers including one led by Taiwan's Hon Hai.

All three bidder groups have roped in Apple to bolster their offers, sources have said.

Toshiba's board is due to meet on Wednesday to consider the offers.