A tiny tadpole is at the centre of the latest legal fight to stop a massive hydroelectric project in northeastern British Columbia.

An environmental activist with a history of defending amphibians alleges that the provincial government knowingly overstepped its authority when it gave permission in May for BC Hydro to move tadpoles and frogs from a section of the Peace River upstream from the new Site C dam. Water from the area is slated to be removed in order to build dikes.

Josette Wier and Sierra Club BC filed a petition in B.C. Supreme Court on Wednesday, asking for a review into whether the Ministry of Forest, Lands and Natural Resource Operations followed the law when it exempted BC Hydro from prosecution for relocating the amphibians, which include toads and salamanders.

The action is the latest in a series of legal salvos from First Nations, environmentalists and land owners to block the multibillion-dollar electricity project that would flood farm land and First Nations hunting and fishing grounds to create the dam and an 83-kilometre-long lake.

The latest petition says a permit is required for such an exemption but a ministry official deliberately issued illegal authorization to avoid possible delays to the dam's construction schedule.

"Amphibians are dear to my heart," Wier said during a phone interview from her home in Smithers. She described the petition as a fight both for the animals and against the Peace River megaproject.

"As citizens we really, really have to stand up. The Site C dam is such a shameful story in its own (right) that anything that can stop it, I will stand for."

In an email, the Forests Ministry said it acted in the public interest.

"Given the extenuating circumstances, the regional manager ... decided to communicate his comfort with the amphibian removal proceeding on a limited scope and in advance of a broader permit which has now been issued," the statement read.

"The alternative would be to allow the amphibians to die."

None of the allegations have been proven in court.

The petition says BC Hydro applied last September for a permit to move the amphibians, which was to be granted by June.

In May, the power utility sought and received permission to move the creatures prior to receiving the official permit in order to avoid construction delays, the document says.

An affidavit accompanying the petition contains an email chain in which Chris Addison, a Forests Ministry director for the region, appears to confirm the absence of a legal mechanism that would allow for an official exemption, short of granting a permit.

In the document, Addison explains that he has granted informal exemptions in the past, and that while the action remains prohibited, if cited it could be defended by saying permission was understood to have been granted by a regional manager.

The petition objects to this approach, accusing Addison of providing a false legal interpretation of the Wildlife Act.

Addison declined comment when reached by phone.

In an email, BC Hydro spokesman David Conway said the utility was looking for emergency permission from the province to relocate the animals.

"It’s important to understand that the intent of BC Hydro, its contractor and the provincial regulator was to protect amphibians," he wrote. "That is, we were asking the regulator for permission to move the amphibians out of harm’s way."

One of the species listed for relocation is the Western Toad, which is considered a species of special concern under the federal Species at Risk Act.

"Damage to any species, especially a species at risk, has grave implications for the ecological integrity of the Peace Valley, given the onslaught of oil, gas and hydro projects in the region," Bob Peart, head of Sierra Club BC, said in a statement.

It's estimated Site C will cost more than $8 billion to build and generate 5,100 gigawatts of energy annually following its anticipated completion in 2024.