(Corrects quote in paragraph 8 to 'million' from 'billion')
* 2012 FY profit 365 mln stg vs 327 mln a yr ago
* Raises dividend by 15 pct
* Expectations for 2013 unchanged
* Flags double-digit growth in revenue over 5 yrs
* Shares up 14 percent
LONDON, March 7 (Reuters) - Temporary power provider Aggreko said it would increase its dividend by 15 percent and reassured investors reeling from two earlier profit warnings, sending shares 14 percent higher.
The British company, whose kit powers major events and covers electricity shortfalls, warned in December that fewer U.S. troops in Afghanistan, a likely fall in business as Japan recovers from the 2011 earthquake, and the absence of a summer Olympics would combine to cut 100 million pounds from revenue.
"Our results in 2013 are going to be slightly below those of 2012 ... we're reiterating that guidance from December," chief executive Rupert Soames said on Thursday, soothing investors rattled by two profit warnings in as many months.
Shares rose 14 percent at 1104 GMT, the biggest gainer on a flat FTSE 100, helped by a better-than-expected dividend increase of 15 percent to 23.9 pence.
"These are the kind of messages that Aggreko has needed to put out to support confidence in the long-term growth prospects that have recently moved behind the clouds of a number of near-term challenges," said analysts at Oriel Securities.
In a note titled "Relief" Investec analysts said the update was encouraging and upped its recommendation on the stock to 'buy' from 'hold'.
Shares are still 17 percent lower than their peak last year.
Soames conceded the going would still be tough in 2013. "We've got some strong very headwinds (this year), because we won't have 60 million pounds of revenues from the London Olympics."
Aggreko supplied more than 600 generators to help keep stadiums and venues lit up last summer.
But the group noted a very strong start at its local business this year. It flagged double-digit growth in revenues with margins and return on capital employed (ROCE) in excess of 20 percent over the next five years in a strategy update.
Pretax profit for 2012, pre-exceptional items and amortisation, rose 11 percent to 365 million pounds ($549.49 million), in line with market expectations. Underlying sales were 14 percent higher at 1.6 billion pounds.
Its local business division, which operates mainly in mature markets, was boosted by a strong performance in North America, with reported revenues up 23 percent overall.
Growth slackened in the second half at Aggreko's international power projects business, which operates in developing markets. It forecasts that segment will continue to slow in the first half of this year, but prospects had "perked up a bit" in recent weeks, noted Soames.
The unit's results were hit by the cost of a new plant in Mozambique and higher bad debt provisions, which it previously flagged, highlighting some volatility in the asset rental business.
Rising demand for power in developing countries, where supply remains hamstrung by a lack of financing and the time required to install permanent capacity, has pushed up demand for services provided by companies like Aggreko and market No.2 APR Energy.
($1 = 0.6643 British pounds) (Reporting by Lorraine Turner; Editing by James Davey and Helen Massy-Beresford)