Canada's top court has ruled that an Alberta landowner does not have the right to sue the province's energy regulator for infringing her constitutional rights.

In a 5-4 split decision, Supreme Court of Canada justices rejected Jessica Ernst's challenge to sue the Alberta Energy Regulator for denying her right to freedom of expression.

The court said Ernst should have pursued a judicial review of how the quasi-judicial regulatory board handled her complaints about fracking.

The ruling also defended the immunity clauses that protect many government bodies from lawsuits.

"When the board made the decision to stop communicating with Ernst, in essence finding her to be a vexatious litigant, it was exercising its discretionary authority under its enabling legislation," it reads.

"Issues about the legality, reasonableness, or fairness of this discretionary decision are issues for judicial review. Ernst had the opportunity to seek timely judicial review of the board's decision. She chose not to. Instead, she attempted to frame her grievance as a claim for charter damages."

Provisions are in place to prevent an "end run" by litigants around the required process that can result in undue expense and delay for the regulator and the public, the decision says.

Inhibit 'effective government'

Writing for the majority on the bench, Justice Thomas Cromwell said granting charter damages may vindicate charter rights, provide compensation and deter future violations.

"But awarding damages may also inhibit effective government, and remedies other than damages may provide substantial redress for the claimant without having that sort of broader adverse impact," the judgment reads. "Thus there is a need for balance with respect to the choice of remedies."

Ernst has claimed hydraulic fracking so severely contaminated her well and water supply with toxic chemicals that she could set it on fire.

She argued the Alberta Energy Regulator violated her charter right to freedom of expression by refusing to accept her complaints and pressuring her to stop making criticisms publicly and through the media.

Ernst said efforts to engage with the regulator were ignored and her letters were returned unopened.

Reacting to the ruling, she said because there were divisions on the bench and mixed interpretations, she hopes another challenge will make its way to the top court.

'I nearly fainted'

"I nearly fainted from the horror of what this means for all Canadians," she said.

"This blasts open our charter and puts a really serious kink into it, which other regulators are going to gleefully go ahead and violate charter rights to their hearts' content. Because now we have this ruling, they're free to do that."

Ernst began legal action in 2007 in a multimillion-dollar suit against the regulator, Alberta Environment and Calgary-based energy company Encana for negligent actions.

In an earlier ruling, an Alberta court rejected Ernst's claim against the regulator, citing immunity provisions in the province's Energy Resources Conservation Act.

Similar immunity clauses

Ernst said hundreds of other regulators across Canada have similar immunity clauses.

Dissenting justices who voted in favour of the appeal, including Chief Justice Beverley McLachlin, said it is "not plain and obvious" that Charter damages could not be an appropriate and just remedy in the circumstances of Ernst's claim, or that the immunity provision bars a claim for charter damages.

The B.C. Civil Liberties Association had intervened in the case, arguing government regulators shouldn't be allowed to block individuals from seeking compensation when their fundamental rights and freedoms have been violated.

Lawyer Laura Track said the decision is disappointing because it denies Ernst the ability to use the charter to defend her right to freedom of expression.

"The charter guarantees everyone the right to an appropriate and just remedy if their constitutional rights are violated, but a majority of the court has now said that in some circumstances, government actors may be immune from charter scrutiny," she told CBC News in an email.

'Extremely concerning implications'

"This decision has extremely concerning implications for people across the country seeking to hold governments accountable for potentially unconstitutional action."

But the top court ruling said Ernst "failed to discharge her burden of showing that the law is unconstitutional."

Ernst's legal battle doesn't end today. She will continue to pursue the lawsuit, a fight she expects will be "most unpleasant and stressful."

Cassie Naas, spokeswoman for the Alberta Energy Regulator, said it would take time to carry out a "thorough review" of the decision before making a public statement.