July 3 (Reuters) - Kinder Morgan Canada Ltd said in a filing on Tuesday it is restarting construction in August on the Trans Mountain pipeline's expansion after halting work in the spring due to opposition from environmentalists and other groups as Canada prepares to buy the project in a bid to boost country's oil exports.

The expansion work will begin in Alberta in August and the North Thompson region of British Columbia in late September, according to a construction schedule https://bit.ly/2MJEA72 for the next six months filed with the National Energy Board.

Calgary-based Kinder Morgan Canada said additional construction was also planned in Lower Mainland of British Columbia.

Kinder Morgan had halted all non-essential work on the C$7.9 billion project in May, citing regulatory uncertainty and opposition from the province of British Columbia.

The Trans Mountain pipeline runs from Edmonton, Alberta to a deepwater port in the Vancouver area. The expansion would nearly triple its capacity, giving Canadian producers greater access to Asia and other world markets.

Canada in late May agreed to buy the pipeline for C$4.5 billion ($3.4 billion) to save the project that faces formidable opposition from environmentalists and British Columbia officials, who are worried the pipeline could spill its tar-like heavy oil.

The deal is expected to close "mid to late summer."

"We're excited to be moving forward in Alberta and the North Thompson, bringing and delivering on our commitments to local, regional and Aboriginal jobs and benefits," Ian Anderson, president of Kinder Morgan Canada, said in a statement.

($1 = 1.3142 Canadian dollars)

(Reporting by Anirban Paul in Bengaluru; Editing by Lisa Shumaker)