There had been talk of a rare summer sitting of the legislature to debate and vote on the $6.2-billion megaproject planned in Labrador.
It now appears the latest facts and figures on the development won't be ready until mid- to late-summer.
Dunderdale says the project has been studied for decades, but recently gave in to opposition demands for a special debate and vote on Muskrat Falls.
Supporters say plans to bring power from Labrador to Newfoundland and then mainland markets would be cheaper than if the island stays isolated.
Critics have raised concerns about cost overruns and whether the power will be too expensive compared to other options.