Comapnies are spending up to 10 per cent of every working day dealing with junk emails, a report has disclosed.
One in seven emails was unwanted and the problem was getting worse, businesses were warned.
A survey of 160 managers by email security company MessageLabs found three out of four feared the problem would get bigger over the next year.
Unsolicited emails, known as "spam", include promotional, marketing or irrelevant information as well as mass circulation business notices.
Jos White, marketing director of MessageLabs, said: "Spam is beginning to emerge as a serious problem.
"It affects thousands of people and has a major impact on the bottom line in terms of wasted time and resources."
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