Tokyo, Mar 14 (IANS): Japanese tech giant Toshiba on Tuesday requested another postponement for the release of its quarterly earnings so that it could investigate an accounting problem at its troubled nuclear energy subsidiary.

The conglomerate said in a statement that it decided to conduct a more detailed investigation to determine whether there was "inappropriate pressure" exerted by senior managers at its US-based nuclear subsidiary Westinghouse over the accounts of Stone and Webster, a US nuclear construction company that was purchased in late 2015, Efe news reported.

Toshiba bought the construction firmto expand its business into the nuclear power industry, resulting in a massive loss.

Toshiba has requested a new deadline of April 11 to submit its financial report for the first three quarters of the fiscal year 2016, for which it estimates a net loss of 500 billion yen ($4 billion), including a 712 billion yen loss derived from Westinghouse.

Toshiba earlier requested a one-month extension in February due to difficulties in completing the audit.

The company said that it would need to investigate the matter further and would require "an additional four weeks" to complete its probe.

Toshiba also stated that the impact of Westinghouse's devalued assets will not affect earnings from the first quarter of 2017.

The company's shares plunged by 8.1 per cent on Tuesday morning on the Tokyo Stock Exchange following its announcement.