The environmental review panel examining the proposed Northern Gateway pipeline has added another 10 weeks of hearings.

The panel will now return to Prince Rupert, B.C., in February of next year to hear participants questioned under oath.

Panel spokeswoman Annie Roy says the additional hearings were needed after participants gave clearer estimates of how much time they would need for questioning.

Hearings wrapped up earlier this month in Prince George, where Enbridge Northern Gateway opened an office on Friday. The company has other offices in B.C. in Vancouver and Kitimat.

Northern Gateway official Janet Holder says the Prince George office will be the new headquarters for the $5-billion pipeline project which is proposed to run from Alberta and to B.C.'s coast.

Review hearings will resume in Prince Rupert on Dec. 10.

The panel will hear oral statements in Victoria, Vancouver and Kelowna in the new year, before returning to Prince Rupert on Feb. 4.

The panel will release its report the last week of December 2013 -- a deadline set by the federal government.