TOKYO, May 7 (Reuters) - Japan's Hitachi Ltd said it expects to report a group net loss of 788 billion yen (S$11.7 billion) for the business year ended March 31 instead of a previously estimated loss of 700 billion yen.

The bigger loss is expected as deferred tax assets are being written down to avoid risks that could arise from a future tax increase, Japan's biggest industrial electronics firm said in a statement on Thursday.

Hitachi will hold a briefing on its earnings estimate at 1 p.m. (0400 GMT).

The company, which will report its annual results on May 12, had a group net loss of 58.1 billion yen in the previous business year.

Hitachi's shares were up 5.5 percent at 364 yen at end of morning trade, before the revision was announced, outperforming a 4.5 percent rise in the benchmark Nikkei average.