(Corrects spelling of Handelsbanken analyst to Engellau, not Engelau)
* Q1 pretax $240 million versus f'cast $235 million
* Sees sales increase of approximately 15 percent
* Organic sales seen up about 8 percent
* Indicative operating margin of around 11.5 percent
* Shares up 6.7 percent, hit highest in more than a month
(Adds analyst quotes, updates shares)
By Patrick Lannin and Helena Soderpalm
STOCKHOLM, April 20 (Reuters) - Autoliv Inc, the world's biggest maker of car seatbelts and airbags, raised its 2011 sales forecast and reassured on profitability, defying worries about supply issues following the Japan earthquake.
Shares in the Sweden-based group, which supplies auto makers worldwide, jumped 6.6 percent to 474.50 crowns by 1137 GMT, after rising as high as 481 crowns, their highest in more than a month.
"This is an unbelievable sign of strength from the company and the share reaction is fully appropriate," said Handelsbanken analyst Hampus Engellau.
Reporting first-quarter earnings ahead of forecast on Wednesday, Autoliv said industry expectations assumed global light vehicle output would rise 4 percent this year, despite an expected fall of 21 percent in Japan, as the decline would be made up late in the year.
"For the full year, the current indication is a sales increase (for Autoliv) of approximately 15 percent with organic sales growing by about 8 percent and an indicative operating margin of around 11.5 percent," the company said, though it also said uncertainty had increased since the start of the year and stressed its forecasts were uncertain.
The earlier outlook for topline growth this year had been more than 10 percent.
The group, which gets 70 percent of its revenues from Europe and the Americas and about 10 percent each from Japan and fast-growing China, reported a first-quarter pretax profit of $240 million versus a year-ago $179 million, beating the $235 million seen in a Reuters poll of analysts.
For the second quarter, it saw sales up 9 percent, helped by currency effects and acquisitions, for an operating profit margin of 9 percent after 12 percent in the first quarter.
"Looking at the market reaction ... there is probably a relief rally, but we should also not neglect the fact that they continue to come out stronger than expectations," said Evli Bank analyst Magnus Axen.
"That makes people start to discount the idea that it could also be longer-term better than expected," Axen added. (Additional reporting by Johan Ahlander; Editing by David Holmes)