* Q4 net down 29 pct to 355 mln euros vs fcast 385 mln
* CEO in Argentina amid pressure on YPF unit
* Shares down 2.8 pct vs sector up 0.2 pct
MADRID, Feb 29 (Reuters) - Repsol's quarterly net profit fell more than expected after Libya's civil war disrupted oil production, adding to pressure on its shares from speculation that Argentina might renationalise the oil company's YPF unit.
Repsol said chief executive Antonio Brufau was in Argentina for meetings, missing Wednesday's announcement of a 29-percent drop in adjusted quarterly net profit to 355 million euros ($477 million), compared with a forecast for 385 million.
The company's shares, which have shed 14 percent since late January, traded down 2.8 percent to 19.95 euros by 1411 GMT on the Madrid bourse, bucking a 0.2 percent rise in the STOXX 600 European oil and gas stocks index.
Repsol said it lost production worth 220 million euros in Libya during the fourth quarter, but oilfields it was responsible for were currently pumping 300,000 barrels per day, close to pre-war output of 340,000 bpd.
Adjusted fourth quarter earnings before interest and taxes fell 26 percent to 781 million euros, also missing forecasts.
Strikes in Argentina also hit full-year net profit of 2.2 billion euros, down 53 percent from 2010, Repsol said.
Media reports have suggested Argentine President Cristina Fernandez may announce a policy move on YPF when she opens a session of Congress on Thursday.
Chief financial officer Miguel Martinez told a conference call that Repsol was "comfortable" with keeping a majority stake in YPF.
Asked about demands from Argentine provinces for energy firms to raise output by 15 percent in the next two years, Martinez said this could be a starting point for negotiations.
"I think this is a general idea to work on. We now have to move with each province to analyse which level of investment is required for each field," he told analysts.
Repsol said its reserve replacement rate rose to an all-time high of 131 percent in 2011 due to new discoveries in Brazil and in "unconventional reserves" found in shale deposits in Argentina.
The company said it would invest 2.4 billion euros in upstream activities in 2012, and another 900 million in downstream, and it would drill 24-34 exploration wells this year.