* Brazil auto inventories at three-year high in April
* Layoffs could last up to five months, union says
* Workers to receive grant, top-ups equal to salary
RIO DE JANEIRO, May 30 (Reuters) - The Mercedes-Benz unit of German automotive group Daimler AG will lay off 1,500 workers at a Brazilian truck factory for up to five months because of declining production, according to the union representing workers at the plant.
In April, the unsold inventory of Brazil's automobile industry reached its highest level since November 2008. Truck purchases speeded up last year before stricter motor emissions standards came into effect.
Concern about a downturn led Brazil's government to announce nearly $1 billion of tax cuts on May 21 to help the struggling auto sector and other industries. Those measures, though, are unlikely to show results until sometime in the second half of 2012, the union said in a statement late on Tuesday.
Brazil's auto industry is the country's largest manufacturing sector.
During the Mercedes-Benz layoffs, the workers at the plant in Sao Bernardo do Campo, on the outskirts of Sao Paulo, will receive 1,163 reais ($585) a month from a state employment stimulus fund known as FAT to attend 300 hours of professional training.
Mercedes-Benz will also make payments to the laid-off workers. Added together, the government education funds plus the Mercedes-Benz payment will equal a worker's full salary.
A Daimler spokesman in Stuttgart confirmed the layoff program. The Daimler group employees 15,000 people in Brazil at three plants.
Daimler shares fell 1.76 percent to 38.25 euros in German trading on Wednesday.