Lawyers for the Yukon Energy Corporation go to court this week in Whitehorse to fight a major lawsuit.

North American Construction, the contractor that installed a new turbine at the Aishihik hydro plant in 2011, claims it's still owed millions of dollars.

The $7-million contract called for the new turbine and generator to be operational by fall of 2011, but court documents filed by both parties show the job was plagued with scheduling changes and delays.

North American Construction says those scheduling changes added almost $4 million to the price of the work. 

Yukon Energy denies blame for the delays, citing lost production due to "inefficient" and "unproductive" workers.

Yukon Energy has since launched a counter suit, claiming the contract price should be reduced by at least half a million dollars.

At least a dozen witnesses from the two companies are scheduled to testify.

A deputy judge from Alberta, Justice Gerard Hawco, has scheduled four weeks to hear the evidence.