MONTREAL -- Liberal leader Justin Trudeau says he would consult both Parliament and the provincial premiers before ratifying the Trans-Pacific Partnership trade deal.

He also says he's looking for more information on the compensation packages that Prime Minister Stephen Harper is offering to Canadian auto parts makers to ease their transition to the deal's new tariff structure.

Trudeau says Harper hasn't done a good job of explaining to Canadians how they will benefit from the deal.

Twelve nations, including Canada, reached a tentative deal on a massive Pacific Rim trading bloc billed as the largest-ever deal of its kind.

Trudeau was speaking in the cavernous and empty Olympic Stadium in Montreal.

He pointed to the building's 60,000 vacant seats, saying that's how many children in Quebec alone would be helped by the party's proposed child benefit.