ST. JOHN'S, N.L. - The government of Newfoundland and Labrador says it will go ahead with an official inquiry into the troubled Muskrat Falls hydroelectric project.

Premier Dwight Ball announced the inquiry at a Liberal Party fundraising dinner Thursday night, saying an audit would not yield enough information as to why the project became so delayed and over-budget.

Ball says the government is finalizing the terms of reference and other details, including which judge will be tasked with heading the inquiry.

He says an inquiry is the best way to answer many questions people have about the soaring costs of the $12.7-billion hydroelectric project, which isn't expected to generate power until 2020 at the earliest.

The cost is about $5 billion higher than when the former Progressive Conservative government approved Muskrat Falls five years ago.

Nalcor Energy CEO Stan Marshall took over as head of the Crown corporation last year after the governing Liberals criticized oversight, saying at the time the megaproject was a colossal mistake.