The loss is largely due to a goodwill impairment of around £4.2bn on a US nuclear unit that came to light in late 2016. Toshiba lost £3.4bn in the same period last year.
The company, which will announce earnings on Tuesday, is expected to respond by selling part of its chip operations and overhauling its nuclear business.
It comes as the Sunday Times reports ministers are preparing a consultation over the government taking minority stakes in nuclear projects to support construction, with a Moorside plant backed by Toshiba among the sites to be considered.
The Japanese firm is among the members of the Nugen consortium set to build on the Cumbrian site. But a potential retreat by Toshiba may require taxpayer funding to be used to make sure it goes ahead.
The mooted consultation will reportedly see the government consider stakes of up to 30 per cent in new projects.
A spokeswoman for the department of business, energy and industrial strategy told City A.M.: “The government believes that new nuclear has an important role to play in our future energy mix as a source of secure, low carbon electricity having commissioned the first new nuclear project in over twenty years at Hinkley.
“We are working closely with a number of developers of these proposed projects in the UK, as they develop their plans.”
The UK is embarking on a programme to build a new fleet of nuclear reactors. Two are set to be built at the Somerset site of Hinkley Point after Prime Minister Theresa May last year greenlit construction, despite question marks over guarantees provided to EDF and Chinese investors on the minimum price of electricity from the plants.