The fashion retailer posted a 60.3% plunge in underlying operating profits to £12.1 million for its first quarter to June 24 after UK like-for-like sales slumped 7.5%.
On a bottom line basis, the group fell into the red with losses after tax of £15.2 million against profits of £5.8 million a year earlier.
It blamed tough conditions on the high street, but its ranges have also missed the mark in recent months.
Chief executive Anders Kristiansen said: “As expected, the UK market has remained difficult, which has resulted in a disappointing quarter of trading.”
He added: “We expect the consumer economy to remain fragile and challenging market conditions to persist into 2018.”
The group is overhauling its clothing ranges, hiring new chief creative officer Paula Dumont Lopez, who is due to start in September.
It is also reducing its “dependence” on the UK high street and Mr Kristiansen said the group is “confident that we will see improvements, but expect these to take time”.
The group saw website sales also fall in the quarter, down 0.6%, while overall brand sales dropped 8.2%.
New Look, owned by South African investment group Brait, has 890 stores, including 593 in the UK and a further 297 globally.