UPDATE 1-Germany's IG Metall union seeks 5.5 percent wage rise

* Union board's demand below last year's, above inflation

* Demand covers 3.7 mln workers

* Employers' union says no justification given weak economy

FRANKFURT, March 4 (Reuters) - Leaders of the IG Metall trade union on Monday called for a pay rise of up to 5.5 percent for some 3.7 million German workers, below last year's demand but still likely to result in an above-inflation increase.

German unions are pushing for higher pay rises ahead of a federal election in September that makes politicians more likely to back their demands, but business lobbies say their calls are unrealistic given anaemic economic growth.

"A demand of up to 5.5 percent more money is appropriate for the workers in the metal and electrical industries," Berthold Huber, chairman of Germany's biggest union, said, adding that this would help stimulate private consumption.

Throughout three years of economic crisis, Berlin has faced calls from struggling euro zone peers to encourage wage increases that would stimulate demand in Europe's biggest economy and make it import more.

IG Metall's board will let regional bargaining committees confer over the demand it has recommended to take into wage negotiations, before officially rubber-stamping it on March 15.

The union said it wanted the deal to be for just 12 months. Huber had already said last week it was not asking for a deal to cover all of 2014 because it was so difficult to predict economic developments.

The Gesamtmetall employers' association criticised the union's demand, saying production in the sector actually shrank slightly in 2012, and only minimal growth was expected for 2013.

"Hardly any growth, and yet they demand 5.5 percent - that doesn't make sense," said Gesamtmetall president Rainer Dulger. "I have the impression this demand has been blown up artificially with hot air."

The union called for a 6.5 percent rise last year before finally getting 4.3 percent over 13 months - the biggest award in 20 years worth a total of 7 billion euros. Its claim is made up of the inflation rate, an increase in productivity - which the union sees at 3.5 percent this year - with the rest to boost private consumption.

The employers' union contended that for private consumption, job security was more important than wage rises.

After a decade of wage restraint, with increases lagging inflation, German paychecks outstripped a 2.0 percent inflation rate in 2012 to rise by 2.6 percent.

IG Metall showed last week it would not be shy of backing up its wage hike demands with a show of force, saying Western German steelmakers like ThyssenKrupp faced possible warning strikes starting this Wednesday.

For a factbox on major wage negotiations coming up in Germany this year, please click on.