UPDATE 1-Colruyt operating profit margin keeps shrinking

* 2008-2009 net 306 mln euros vs avg forecast of 308 mln

* Revenues 6.3 bln euros, in line with avg forecast

* EBITDA 549 mln euros vs avg forecast of 559 mln

* Op. profit margin 6.8 pct vs 7.1 pct in 2007-2008

(Adds details, background)

BRUSSELS, June 24 (Reuters) - Discount supermarket chain Colruyt (COLR.BR: Quote, Profile, Research) reported a fall in its operating profit margin due to higher staff costs costs and said net profit and operating cash flow were just shy of market expectations.

The Belgian retailer, which competes with German discounters Aldi and Lidl, France's Carrefour (CARR.PA: Quote, Profile, Research) and Belgium's high-end Delhaize DELBt.BR, said its investment programme -- currently at 230.6 million euros -- would continue to grow.

"Despite the economic crisis the Colruyt Group continues to invest in future growth and sees its turnover and profits increase further," the firm reported on Wednesday in its 2008-2009 results.

It said net profit for its full year, which ended on March 31, rose 6.2 percent to 306 million euros. This just undershot the 308 million euro average estimate of 12 analysts polled by Reuters, but beat Colruyt's earlier guidance of 304 million.