Nova Scotia Premier Rodney MacDonald says the federal Liberals may face a local backlash over their deal with the Greens to try to oust Conservative MP Peter MacKay from his seat.

Under the deal, which was confirmed by the parties on Friday, the Liberals agreed not to field a candidate in MacKay's riding of Central Nova, where Green party Leader Elizabeth May intends to run.

It's a tactical move designed to help try to unseat MacKay, currently the foreign affairs minister, in the next federal election.

MacDonald, a Progressive Conservative, said Friday that such political games might not please voters in Central Nova.

"When you have a national party that's not running candidates in every riding, I think they'll have some explaining to do within their own political party," he told reporters.

"I think there could be some backlash because of their decision."

As part of the deal, the Greens have agreed not to run a candidate in Liberal Leader Stéphane Dion's Montreal riding.

Mixed reaction from provincial Liberals

Michel Samson, the interim leader of the Nova Scotia Liberals, said he supports what his federal counterpart is doing and called the deal a wise political move.

But one member of the provincial Liberal caucus said he considered the deal inappropriate.

Keith Colwell, the MLA for Preston, said he wants to see a Liberal on the ballot in Central Nova in the next federal election.

"I think they should run a Liberal in every riding regardless, and especially in that riding because I think it's time we get a new member there," Colwell said.

MacKay has represented the area in northern Nova Scotia since 1997. The borders were altered slightly in 2004 and the riding became Central Nova.

In the last federal election in 2006, the NDP came in second with almost 33 per cent of the vote, compared to MacKay's 41 per cent.

MacDonald said whatever deal the Liberals strike with the Green party, he believes MacKay will win his seat.