The Onion Lake Cree Nation in Alberta and Saskatchewan is taking the federal government to court over a new law that requires First Nations bands to post their audited financial statements online, including the salaries and expenses of their chiefs and councillors.

The government told CBC News that as of Wednesday at 5 p.m. ET, 61 First Nations had until midnight to comply with the First Nations Financial Transparency Act. Nearly 90 per cent — 521 out of 582 First Nations — have already done so.

Chief Wallace Fox from Onion Lake Cree Nation, in Treaty 6 territory, which counts over 5,500 members said a statement of claim was filed in Federal Court in Edmonton earlier today.

"We decided, enough is enough," Fox said during a news conference in Edmonton.

"The statement of claim was the last step in a long journey to get the federal government to sit down and talk with the nations."

The court document names the Governor General, the aboriginal affairs minister and the attorney general of Canada.

After midnight Wednesday

Fox said the legal action was in response to the government's "ultimatum" and "threatening letters."

As CBC News reported on Tuesday, the government has outlined the range of measures it can take against First Nations that don't comply with the new law.

In a letter obtained by CBC News, the government said that on Thursday it will post on the Aboriginal Affairs website the names of bands that have not complied.

According to the letter, the government could "withhold funding for non-essential programs, services and activities until the requirements are met," starting tomorrow.

And starting on Dec. 12, the government could halt new or additional funding or end funding agreements entirely.

Asked about the court action against Ottawa, the office for Aboriginal Affairs Minister Bernard Valcourt said he had no immediate comment.

Valcourt has publicly said First Nations that don't follow the law could be subject to "court orders, withholding of non-essential funding and withholding of new funding."