* Q4 REBIT 166 mln euros vs 165 mln forecast
* Margins increase in Asia, Europe
* Cuts debt by 25 pct in six months
* To buy Pirelli's steel cord business
* Shares rise as much as 9.5 percent (Adds Pirelli deal, details on debt, share reaction)
BRUSSELS, Feb 28 (Reuters) - Belgian steel cable and wire maker Bekaert on Friday reported a 42 percent increase in 2013 adjusted operating profit, as restructuring boosted its margins in Asia and Europe and it cut debt.
The company, whose steel wire reinforces a quarter of the world's automotive tyres, said it saw strong demand from Chinese and the European automotive sector picked up in the second half of 2013.
Bekaert cut its debt by a quarter to 574 million euros from 770 million at the end of the first half by reducing its working capital.
The group's shares rose by as much as 9.5 percent on Friday, making them the strongest performer on the Bel20 Index of leading Belgian shares.
"There were no negative surprises this time and the debt reduction was admirable," an Amsterdam-based trader said.
About two-thirds of Bekaert's market value has been eroded since its peak in 2011, after a crash in the market for sawing wire used for solar panels. That prompted a restructuring to cut 1,850 jobs and save around 100 million euros a year.
Margins in the Asia Pacific region rose to 8.1 percent from 3.9 percent, while profitability in the Americas fell.
In Europe, the Middle East and Africa, margins also rose, though not by as much as in Asia.
Operating profit adjusted for one offs (REBIT) rose to 166 million euros ($227.11 million), in line with the average forecast in a Reuters poll of six analysts.
Bekaert said it would buy the steel cord activities of Italian tyre manufacturer Pirelli, and had signed a deal to supply steel cord to the Italian company on a long-term basis.
The group said the deal had an enterprise value of 255 million euros and would add about 300 million per year to Bekaert's revenues. ($1 = 0.7309 euros) (Reporting by Robert-Jan Bartunek; Editing by Erica Billingham)