OTTAWA - Prime Minister Stephen Harper departed Sunday for South Korea, where he is widely expected to complete another long round of free-trade negotiations that his critics were denouncing as secretive and potentially bad for Canadian workers.

It wasn't known whether Harper planned to sign the final text of a free-trade deal with South Korea - a laborious, decade-long, on-again, off-again process - or was simply going to announce an agreement-in-principle in a staged photo-op.

That's essentially what occurred last fall when Harper jetted off to Brussels on short notice to mark the end of four years of rocky negotiations with the European Union.

The fanfare of that announcement was not accompanied by a final text, something Harper and the Europeans said at the time could take at least another year and a half. However, Trade Minister Ed Fast said last month the legal text should be ready soon, possibly in the next month or two.

A government source close to the talks, who was not authorized to speak on the record, noted that Harper tabled a summary of "final negotiated outcomes" in the House of Commons within two weeks of the Brussels signing ceremony.

NDP trade critic Don Davies said growing trade with South Korea and Asia in general is a good thing. But he was skeptical that the week's coming ceremonies would not amount to much more than a repeat of Brussels.

"Are they going to go just to shake hands, have a photo-op and sign an agreement-in-principle without the actual details or text to be released?"

Davies assailed the government for a total lack of transparency, and questioned whether the deal would be able to protect jobs in Canada's auto sector.

"In trade deals, it's details that matter," he said.

"The Conservatives have the least transparent trade policy probably in the developed world. They are closed, they are secretive and they don't involve a lot of stakeholders; they don't involve the opposition."

The deal would mark progress toward expanding trade with Asia, a major economic priority of the Harper government. Coming on the heels of the Canada-EU pact, it would allow Harper to trumpet his first significant free-trade deal in Asia, and give impetus to other negotiations, particularly with Japan.

"It's a very long time coming," said Yuen Pau Woo, president of the Asia Pacific Foundation of Canada.

"We are well behind our competitors, and closing with Korea will show that Canada is serious about developing stronger trade ties with Asia, and could well accelerate the pace of our negotiations with other countries."

International Trade Minister Ed Fast acknowledged as much in an interview aired Sunday.

"Our exports to Korea have declined quite precipitously since the Americans and the Europeans got their trade agreements with Korea," Fast told CTV's question period.

"So we're looking to level the playing field, make sure that our businesses can compete fairly with some of our biggest competitors."

A key irritant is the auto sector. Canada has a 6.1 per cent tariff on car imports.