Justice Richard LeBlanc is commissioner for the Muskrat Falls commission of inquiry. (Terry Roberts/CBC)

The commissioner leading the inquiry into why the Muskrat Falls megaproject is billions of dollars overbudget says he needs another three months to finish his final report, and that the new deadline is March 2020.

The original deadline was Dec. 31, but that has been changed to March 31, 2020, after Justice Richard LeBlanc asked Natural Resources Minister Siobhan Coady for an extension.

"This inquiry has had to deal with a very complex project and complex subject matter, numerous witnesses and parties, as well as a review of literally over four thousand exhibits," said LeBlanc in the letter.

LeBlanc has been tasked with leading the independent inquiry into the cost and schedule overruns of the $12.7-billion dam and power plant on the Churchill River.

He said the that "the bulk" of the report has been written and that he expects to complete it shortly, and he is sticking to to the budget.

"I am pleased to report ... that direct spending by this Commission of Inquiry, including for legal counsel for parties with standing as well as Commission counsel and stall, is well below the amount budgeted by government," said LeBlanc.

'I better get cracking'

LeBlanc said asking for more time comes with "great regret and significant personal disappointment," but that the extra time is necessary.

In August, LeBlanc heard final submissions in Labrador and had some strong words of advice for himself.

"I better get cracking," said LeBlanc at the time.

The Nalcor Energy photo of the Muskrat Falls power generating project was taken in May 2019. As of April, the entire Lower Churchill Project was 98 per cent complete. (Nalcor)

He acknowledged there was a lot of work to do in a relatively short amount of time, but at the time was hoping to meet a deadline of the end of the calendar year.

"I don't think it's appropriate for me to request any form of extension at this time, and I'm not going to do that," he said in August. "I think for all parties, including my own sanity, I think the date of Dec. 31 is an adequate one."