Internal U.S. documents published by WikiLeaks are raising questions about whether the Alberta government plans to export electricity to the United States.

The leaked internal U.S. diplomatic cables reveal that Murray Smith, Alberta's former energy minister, told U.S. officials in 2003 that excess electricity generated for oil sands operations could be made available for export.

According to the documents, Smith said Alberta lacked the transmission lines needed to export the power to the United States.

"But at least for now there is limited capacity to move this west and then south through British Columbia and on to our Pacific Northwest," the cable notes.

"There is almost no capacity to move it south into the U.S. Rocky Mountain states and markets further afield."

Opposition parties say a proposed multi-billion dollar north-south transmission line will be used to export that power even though the Stelmach government has denied it.

"There's nothing necessarily wrong with exporting surplus power to the United States," NDP Leader Brian Mason said.

"But by hiding it, they're proceeding with a policy that will require Albertans through their electricity bill to pay for this transmission infrastructure which is worth billions and billions of dollars."

On Tuesday, Premier Ed Stelmach didn't deny discussions had taken place, but he said Albertans have nothing to fear.

"If anybody wants to export power out of the province, the cost of that transmission is borne by the exporter, not by the consumers of Alberta. That is very clear."

He insisted the proposed transmission line between Edmonton and Calgary is to serve the province's needs, not the U.S. market.