Alberta's top court is allowing a dozen submissions to be heard from advocacy groups and First Nations in the province's constitutional challenge to Ottawa's revamped environmental assessment rules.

Alberta's United Conservative government has argued no new pipelines would be built under the Impact Assessment Act, part of the contentious Bill C-69.

It filed its challenge to the Alberta Court of Appeal last fall asking whether Ottawa was within its authority in imposing the new regulations.

Justice Patricia Rowbotham said submissions from six interveners would be allowed on Alberta's side, along with another five in support of the federal government.

She also granted intervener status to the Canadian Taxpayers Federation, which says it does not support either party.

Ottawa challenged the taxpayer group's application, as well as a joint application on the Alberta side from the Independent Contractors and Business Association and Alberta Enterprise Group. Rowbotham decided both should be heard.