Fiat SpA's plans to get majority ownership of U.S. No.3 car maker Chrysler are likely to continue to attract investors' attention when the Italian carmaker reports first quarter results on Wednesday.

Fiat SpA is due to report its first set of results since it started to trade separately from truck-and-tractor maker Fiat Industrial in January.

The car maker is seen turning in first quarter trading profit of 245 million euros ($350.8 million), according to the median forecast of an analyst consensus distributed by Fiat.

Analysts said Fiat is likely to suffer from weak sales in Europe and in its home market Italy, although this poor performance will be partly offset by sustained demand in Brazil and in the light vehicles segment.

However, much of the investors' attention will be focused on Fiat's plans to take a majority stake in Chrysler, 30 percent-owned by Fiat and already managed by Italy's biggest industrial group.

We believe that the market is already expecting a difficult and relatively weak first quarter for the group. The current European passenger car market, above all Italy, is still very worrying, said Monica Bosio at Banca IMI, adding a gradual improvement of the outlook was expected from April.

Having said this, following the results, we believe that the market will be more focused on Fiat's likely increase in Chrysler.

Chief Executive Sergio Marchionne, also at the helm of Chrysler, said last week he plans to refinance $7 billion of Chrysler's debt with the U.S. and Canadian governments, a condition for Fiat to be able to take an additional 16 percent in the U.S. auto maker.

Sources familiar with the matter told Reuters on Friday that Fiat expects to pay around $1.5 billion euros to buy the 16 percent stake.

Fiat would then take a further 5 percent in the last quarter of 2011 upon meeting the third of three milestones agreed with the U.S. government when Fiat took over control of Chrysler in 2009 under a bailout accord. Under the deal, Fiat would not have to pay for this stake.

Lack of new products meant Fiat underperformed the overall market in the first quarter, with Global Insight predicting its European car sales market share to have slipped to 6.7 percent in March from around 8 percent previously.

While working on its Chrysler project, the energetic Marchionne is also trying to introduce sweeping new labor rules at its loss-making Italian plants. But its program to boost productivity, known as Fabbrica Italia, is under threat from legal action filed against Fiat by Italy's hardline metalworkers union FIOM.

($1=.6984 Euro)

(Writing by Lisa Jucca, editing by Bernard Orr)