UPDATE 1-Impregilo cuts 2009 margin target, 9-mth net slumps

* Sees 2009 EBIT margin on sales at around 5 percent

* Nine-month net down 77 percent to 37.3 million euros

* Shares closed down 1.3 percent before results

(Adds detail, shares)

MILAN, Nov 6 (Reuters) - Italy's biggest construction company, Impregilo (IPGI.MI), cut its 2009 profitability target, citing difficulties at its engineering unit, when posting a 77 percent fall in its nine-month net profit.

Impregilo said on Friday it now expected an operating profit margin on sales of around 5 percent this year, against a previous target of more than 6.4 percent.

It posted nine-month net profit of 37.3 million euros ($55.5 million) and forecast 2009 revenues at 2.6 billion and a positive net result.

Impregilo, which recently won a contract to widen the Panama canal, said its order book rose 30 percent to 21.1 billion euros at the end of September.

Shares in Impregilo closed down 1.3 percent at 2.487 euros before the release of the results statement. The DJ Stoxx construction and material index .SXOP was down 0.7 percent. (Reporting by Danilo Masoni; Editing by Dan Lalor) ($1 = 0.6722 euro)