The boss of struggling Toshiba said on Thursday he would cut 7,000 jobs over the next five years as the Japanese engineering firm pulled out of foreign investments and downgraded its annual profit forecasts.

Toshiba also expects to scrap or consolidate some factories and reduce its subsidiaries by 25 per cent, announcing the withdrawal from a United States-based liquid natural gas business and the liquidation of NuGen, a nuclear subsidiary in Britain.

“After considering the additional costs entailed in continuing to operate NuGen, Toshiba recognises that the economically rational decision is to withdraw from the UK nuclear power plant construction project and has resolved to take steps to wind up NuGen,” the firm said in a statement.

A joint venture between Toshiba and France's Engie, the NuGen project in Cumbria in northwest England was to comprise three reactors and was due to start producing energy from 2025.

Chief Executive Officer Nobuaki Kurumatani told reporters in Tokyo the decision was reached after “sincere discussions” with the British government.

He added that the firm expected to slash 7,000 jobs over the next five years, many coming from early or planned retirement.

The former Japanese behemoth is going through a sweeping reform effort to revive itself following its disastrous acquisition of US nuclear energy firm Westinghouse, which racked up billions of dollars in losses before being placed under bankruptcy protection.

For the year to March 2019, the firm said it expected a net profit of 920 billion yen, down from an earlier projection of 1,070 billion yen.

Annual operating profit outlook is now 60 billion yen, down from a previous 70 billion yen forecast, while the sales estimates were kept at 3,600 billion yen.

Still, the firm's share price soared, closing up more than 12 per cent on the Tokyo stock exchange, mainly due to the announcement of a share buy-back programme.

To stay afloat, the cash-strapped group sold its lucrative chip business for $21 billion to K.K. Pangea, a special-purpose company controlled by a consortium led by US investor Bain Capital.

The sales of the memory unit continued to boost Toshiba's net profit, although the firm's operations remained under pressure.

For the six months to September, the company's net profit stood at 1.08 trillion yen, reversing a net loss of 49.8 billion yen seen a year earlier.

But its six-month operating profit fell to 6.98 billion yen, more than 80 per cent down from a year ago when the company took emergency cost-cutting steps such as the dramatic reduction of seasonal bonuses to its workers.

First-half sales came to 1.78 trillion yen, down 5.1 per cent from a year ago.