Japan's Toshiba has failed to submit audited third-quarter earnings for a second time.

It has gained a one month extension as its expands a probe into problems at its US nuclear unit Westinghouse. 

With its financial woes only deepening, Toshiba said it would speed up looking at whether to sell a majority of Westinghouse even as it sought to reassure investors it could have a future without the unit or its prized memory chip business which has been put up for sale.

It will "aggressively consider strategic options" for Westinghouse, it said in a statement, although it did not mention a potential Chapter 11 filing for the US nuclear firm. 

Sources have said that bankruptcy lawyers have been hired as an exploratory step.

The conglomerate said its auditing committee had confirmed that certain Westinghouse senior managers had exerted 'inappropriate pressure' in the accounting for an acquisition of a US nuclear power plant construction company in its third-quarter earnings. 

It now needs to check if pressure was exerted in preceding quarters as it would also be filing nine-month results. 

Toshiba will also expand the probe's scope to see if there were 'other inappropriate pressures', it said in a statement without elaborating on what they could be. 

Westinghouse has become the epicentre of Toshiba's latest crisis, after buying a US nuclear power plant construction company from Chicago Bridge & Iron in 2015. 

Two US projects in Georgia and South Carolina handled by the acquired firm have been plagued by cost overruns and Toshiba has already flagged a $6.3 billion writedown. 

Liabilities attached to Westinghouse mean it is unlikely to be an easy asset to sell, despite attractive technology. 

South Korea's KEPCO is seen as the only potential buyer, as it expands in nuclear after a successful deal in the United Arab Emirates. KEPCO said today it would consider an approach by Toshiba. 

"We will review the overall project and weigh how beneficial this project would be to us," a spokesman said.

Toshiba, for whom the latest scandal is its second in two years, said it would also introduce fresh measures to overhaul its governance, including improving board level oversight, internal controls, risk management and headquarters' grip on the activities of its affiliates.

It estimated that it could post an operating profit of 70 billion yen ($610m) in the next financial year excluding Westinghouse and its chips business, and also forecast an operating profit of 210 billion yen two years later.

The new extension to April 11 follows its first postponement of audited earnings a month ago. 

If it fails to meet that deadline and does not gain another extension it would have until April 21 to submit the earnings or be delisted.

A source with direct knowledge of the matter said a one-month extension should be enough to work out differences with auditors.

Toshiba is also due to submit this week a report to the Tokyo Stock Exchange on its internal controls in the wake of its latest financial woes as well the 2015 accounting scandal. 

That could eventually also lead to a delisting if the bourse finds Toshiba's efforts unsatisfactory.