Chief executive of UR Iain Osborne said: "We have a track record that as soon as we see an opportunity to reduce customer tariffs we do.
"At the moment it seems to us there isn't scope until we get to the October price review, partly because the companies have bought forward as we expect them to and locked in their cost base until them."
He concluded that October was the most likely time for tariff review.
Electricity prices in Ulster fell by 22 per cent in December of last year.
However, energy prices were hiked twice in 2008, once by 14 per cent and then by 33 per cent.
At the end of last month, E.ON launched a reduced-price online energy tariff called FixOnline.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.