The furniture retailer estimated underlying earnings (EBITDA) for the year will be "below" the £82.4mln reported in 2017.
The company said in the final quarter it suffered a disruption to ships bringing made-to-order products from the Far East, while the hot weather led to “significantly” lower-than-expected order intake.
As a result, like-for-like sales are expected to fall 3% in the 23 weeks to July 7 and drop 4% in the 49 weeks to the same date.
A slowdown in the housing market and a tough retail market also contributed to weaker sales.
DFS said: “We continue to expect that the furniture retail market will remain challenging over the next twelve months, given ongoing reduced consumer confidence levels, although we would expect some alleviation of current short-term demand effects.”
The group believes investments in its supply chain and the recent acquisition of Sofology will provide “benefits to earnings that we expect to help mitigate the challenging sales environment”.
DFS said it has a track record of capitalising on adverse trading conditions to build its market share and believes its cash generation and long-term growth prospects will drive “attractive returns” for shareholders.
Shares fell 2.8% to 193p in morning trading.