The province's opposition parties are lambasting Premier Rodney MacDonald for accepting a deal with Ottawa they say fails Nova Scotians.

Under the deal, announced Wednesday, MacDonald said the province is expected to gain hundreds of millions of dollars through equalization payments and offshore oil and gas royalties.

But it will take years before Nova Scotia makes as much as it would have under the original offshore accord signed in 2005.

A lot can change in that time, said NDP Leader Darrell Dexter.

"They are basing the idea that they will be better off in 2019 on the theory that that equalization formula won't change. Just as a reference point, that equalization formula itself has changed three times in the last three years," he said.

The premier was in Ottawa to announce the deal with Prime Minister Stephen Harper.

Just months ago, MacDonald accused Harper of reneging on a promise to allow Nova Scotia to keep its offshore energy wealth and not lose equalization money. He said the province lost millions when the federal government scrapped the offshore deal in its last budget.

MacDonald said Wednesday that he got all that money back, and more.

Though the federal government guarantees that Nova Scotia will not lose any offshore royalties as a result of the changes made in the budget, the province must still choose between keeping the old equalization formula and the 2005 offshore accord, or adopting a new, enriched equalization formula.

The deal also calls for a three-person panel to look at the value of the Crown's share, a complex cash royalty that was part of the province's original 1985 offshore agreement. Since production started in the Nova Scotia's offshore resource industry in the early 1990s, Ottawa has not paid the benefit to the province.

The panel is expected to report with a binding decision, which could mean a large cash payment to the province.

Dexter said the panel is a good idea. However, Nova Scotia Liberal Leader Stephen MacNeil is not so sure.

"It was flashback to [former premier] John Buchanan promising us the glory days will be here. We'll have to see how that goes. John Buchanan got re-elected a few times on the issue. Maybe the premier is going to try to do that," MacNeil said.