It's troubling that TransCanada is sending pipes to the U.S. before the State Department approves the Keystone XL extension, an NDP critic said Wednesday.

Truckloads of pipe from Canada are arriving daily in Gascoyne, N.D., where they are being stockpiled, Radio-Canada reporter Marc Godbout reported Monday.

The U.S. State Department is considering the company's request to extend the Keystone XL pipeline through the U.S. but likely won't decide until the end of the year. The Canadian government says it fully supports the expansion.

Megan Leslie, the NDP's environment critic, says the fact TransCanada is already shipping pipes to the U.S. makes people question the whole process.

"It’s unbelievable to me that industry would be lining this up already," she said. "They're saying 'come on board and support this project, you have a say in this,' and meanwhile they're stockpiling pipes.

"It makes me feel like the die is cast."

A spokesman from TransCanada says the company is shipping pipes to multiple pipe yards to prepare for the extension.

"The pipe yards are in preparation [for] Keystone XL and they are located throughout the U.S. and part of Canada," Terry Cunha said in a statement to CBC News.

Most of the pipe – 85 per cent – will be manufactured in North America, he added.

"One of the mills is in Regina. We hope to begin construction in early 2012. We need [the] Presidential Permit from the State Department before we can proceed with construction," Cunha wrote.

Long delays possible

It's possible a decision on Keystone could be delayed, however. And construction could start even later than planned if the U.S. government decides to re-route the pipeline around an ecologically sensitive aquifer in Nebraska, which a spokesman for the State Department wouldn't rule out Wednesday.

A U.S. official told The Associated Press on Wednesday that the U.S. State Department, which is involved because the pipeline would cross international borders, is now mulling a new route.

Such a route change would force Keystone XL to go through environmental and wildlife studies all over again, said Alex Pourbaix, president of energy and oil pipelines for TransCanada. So far the environmental review process has taken more than three years.

"There's no doubt that if we were asked to do that, I think it would a minimum of a one- to two-year delay," he said in an interview. Most studies can only take place during the summer, prolonging the process.

Wednesday's development – as well as news the department's inspector general will review the assessment process over conflict-of-interest concerns – has called that timeline into serious doubt.

The rerouting decision would likely push a final decision on the pipeline past the 2012 presidential election. The issue has become a hot issue for President Barack Obama, who has the power to block or approve the project.

The Obama administration risks angering environmental supporters if he approves the pipeline and could face criticism from labour and business groups for thwarting jobs if he rejects it.

With files from The Canadian Press