DS Smith PLC (LSE:SMDS) said box sales have slowed since May and that input costs have increased significantly but that it still expects a "significant improvement" in performance this year.
The paper and packaging supplier said corrugated box volumes in the first quarter "declined slightly" on a like-for-like basis, compared to growth last year of 13%.
For the whole year to next April the FTSE 100 group said it expect growth of "at least 2%", moderating its guidance from the "2%-4%% it gave in June.
Despite the ramp-up in costs, including energy, the company said it is "substantially" mitigatating this with efficiency initiatives and long-term hedging programmes, with more than 90% of natural gas costs hedged for the current fiscal year and circa 80% for the next.
"We have started the financial year very strongly, despite the current macro-economic conditions," said Miles Roberts, group chief executive, in a statement.
"Whilst the industrial sector is showing some weakness, our FMCG business remains resilient."
Additionally, the company announced group finance director Adrian Marsh intends to retire from the board once his successor has been identified.
DS Smith said it will take steps to identify and appoint his successor, and an announcement regarding the date of Marsh's retirement will be made in due course.
Shares of the company were trading 2.7% higher at 270.2p in early trades.