UPDATE 1-Philips sees weakening in all its sectors in Q1

* CEO expects further sales decline in 2009

* Sees no impact from stimulus plans, sees L-shape recession

* Shares down 3.1 pct, reversing gains

(Adds CEO comment)

AMSTERDAM, March 27 (Reuters) - Philips Electronics (PHG.AS)(PHG.N) Chief Executive Gerard Kleisterlee said on Friday all of the group's three markets showed a further weakening in the first quarter of 2009 compared with the previous quarter. "The economic stimulus packages running into billions in many countries have not yet had a noticeable positive effect," Kleisterlee said at the company's annual shareholders meeting.

"It looks as though we could be in L-shaped recession: a rapid, almost vertical fall to a low level where we are stuck for a long time," he said.

Philips expected a further sales decline this year, Kleisterlee said.

Shares of Philips were down 3.1 percent at 12.19 euros by 1327 GMT, reversing an earlier gain of about 0.5 percent.

Philips is the world's biggest lighting maker, a top three hospital equipment maker and Europe's biggest consumer electronics producer. (Reporting by Harro ten Wolde; Writing by Gilbert Kreijger; Editing by David Holmes)