Workers building the huge Belo Monte dam in Brazil's Amazon jungle will go on strike next week, a union official said Friday.

Roginel Gobbo, vice president of the construction workers union in the state of Para, said 7,000 workers agreed to walk off the job Monday because they haven't reached an agreement with the construction consortium on two key points.

Workers want hometown visits every three months instead of the current six. They also want the value of their monthly meal vouchers more than tripled _ from 95 reals ($51) to 300 reals ($160), he said.

An official for the Belo Monte Construction Consortium said the impasse on the two points "convinced workers to go on strike, which we expect will be a peaceful one." He spoke on condition of anonymity because he was not an official spokesman.

Gobbo said other issues, including wages, will be discussed during year-end contract negotiations.

When completed, the $11 billion, 11,000-megawatt Belo Monte dam will be the world's third largest, behind China's Three Gorges dam and the Itaipu dam that straddles the border of Brazil and Paraguay.