TOKYO, Sept 25 (Reuters) - General Motors Corp said it would export more than $800 million worth of U.S.-built Buick sport utility and other vehicles and components to China starting in 2008 in its second export agreement with China this year.

The Detroit automaker signed the multi-year deal with Shanghai General Motors, one of its Chinese joint ventures, on Monday in Washington D.C., it said in a statement.

The agreement comes as the United Auto Workers union called the first national strike against GM since 1970 on Monday after a 10-week round of contract talks stalled, sending more than 73,000 factory workers to picket lines.

The contract talks are seen as crucial to GM's survival as it restructures its loss-making U.S. operations and seeks to cut itself free from a health-care obligation of over $50 billion.

In an announcement that appeared to be aimed at providing positive news for its local work force, GM said the Buick model, called Enclave in the United States, would be built at its Lansing Delta Township plant in Michigan and added to Shanghai GM's Buick line, which includes the Park Avenue and LaCrosse sedans.

China has provided a rare success story for GM, which sold a record 876,747 vehicles in 2006 to become one of the top brands in the hotly contested market.

In May, GM signed another deal to export $700 million worth of Cadillacs and car parts to China from the United States.

The latest deal would take the value of GM's U.S.-sourced products for the Chinese market to more than $1.5 billion this year, GM China Group President Kevin Wale said in the statement.