The group said sales at shops open at least a year fell 6.1 per cent in the period from 1 August to 24 December, the bulk of its second half.
Analysts had expected a fall of between three and six per cent.
However, sales at Next's Directory home shopping business climbed 8.7 per cent, compared with analysts' forecasts of up 6-9 per cent and third-quarter growth of 7.9 per cent.
Next guided that full-year pretax profit will be in the range of £540-555m, in line with current market expectations.
The group runs 500 stores in Britain and Ireland.