Irish business services group DCC Plc said its earnings would be weaker than expected, after an exceptionally mild winter and a weak economy hit its key UK energy business.

The Dublin-based group, whose energy business delivers more than half of its profits, cut its forecast for adjusted earnings per share to between 155 and 170 cents from its previous guidance of 188 cents for the year to March 31.

Its shares opened down 6.3 percent at 17.29 euros.

Volume at DCC Energy in last three months of 2011, the mildest on record in the United Kingdom, were 12 percent behind the same period in 2011, which was the coldest on record, the company said in a statement.

The weakness is likely to continue in the three months to March 31, it said.

The absence of any sustained cold weather this winter, along with the difficult economic background and high oil prices, are likely to continue to impact adversely both volumes and margins for energy products in the (fourth) quarter, the statement said.

Full-year operating profit for the group is expected to be between 175 million euros and 190 million, while operating profit at DCC Energy will be in the range of 75 million to 90 million.

DCC's other main business, DCC SerCom, which markets and sells computer games, was strongly ahead of the prior year on acquisitions and strong organic growth. Trading in the rest of the group was in line with the previous year, it said.

(Reporting by Conor Humphries)