The FTSE 250-listed company said that like-for-like sales in its shops in the 17 weeks to 27 April 2013 were 4.4 per cent lower, impacted by poor weather in January and March.
Greggs’ shares opened six per cent down after the announcement.
“We do not expect a significant improvement in the difficult underlying market conditions in the short term,” said the company.
“The business is focused on continuing with our plans to invest in core sales performance whilst taking action to reduce costs.
“Although we are only four months into the year, based on current own shop like-for-like performance we believe that profits for the year are likely to be slightly below the lower end of the range of market expectations.”
Analysts' expectations for the baker’s profits in 2013 are in the range of £47.5m to £55.2m.