Woolworths saw its losses widen to £99.7 million for the 26 weeks to August 2, up from a loss of £63.8m the previous year.
Group sales at Woolworths fell 3% to £1.1 billion, while retail like-for-like sales were down 3.2% during the period.
But retail like-for-like sales for the first six weeks of its second half are up 0.4%.
Woolworths chairman Richard North said: "For the first half of the year EUK and 2 entertain are performing ahead of our expectations, while Woolworths Retail manifestly is not. However, the board believes that the strength of our entertainment businesses provides a solid platform of profitability from which the turnaround of the retail business can be based."
North added: "The board of Woolworths is delighted that Steve Johnson has now started as chief executive. Although he has been in the job for less than a month he has already demonstrated the strategic and operational skills and the energy needed to help take Woolworths to the next stage of its development."
Johnson said: "I took this job because I am convinced that there is space on the high street for a successful home-based variety store offering great value and convenience. My first weeks in the job have only reinforced that view and shown me that Woolworths has a core of strong, profitable stores, a great retail brand and many very committed people who want to succeed."
Johnson added: "It is too early for me to have a fully developed strategy. That plan is in progress but still some way from completion and we will update investors as soon as possible. Right now, this business does not require lots of new strategic initiatives, it requires a good dose of basic shop keeping and attention to the detail of retailing. Everyone in Woolworths is clear that our first priority – in all parts of the Group – is delivering a successful Christmas for
Last month Woolworths rejected an offer for its high street stores from Iceland chief executive Malcolm Walker and a Baugur consortium.