Nova Scotia's party leaders were largely off the campaign trail ahead of Thursday night's debate, but the parties duelled by press release as a new poll suggested a tightening race.

The NDP and Progressive Conservatives attacked the incumbent Liberals over health care, while the Liberals highlighted the Tory promise to "cut taxes for big business to unprecedented rates."

A Mainstreet poll released Thursday suggested the Tories have gained ground on the Liberals ahead of Tuesday's vote.

It shows the Liberals were at 37 per cent support from decided and leaning voters, down three points from the most recent Mainstreet poll. The Tories were up four points to 34 per cent, while the NDP was up a point to 25 per cent, and the Greens were down a point to four per cent.

The Mainstreet/iPolitics poll of 1,200 Nova Scotians from May 23 has a margin of error of plus or minus 2.81 percentage points, 19 times out of 20.

That means Liberal support could range from 34 to 40 per cent, Tory strength could range between 31 and 37 per cent, NDP support could range from 22 to 28 per cent, and the Greens could range from 1 per cent to 7 per cent. In one case in 20, the figures could be substantially different.

In a news release Thursday, the Progressive Conservatives said Liberal neglect has left about 100,000 people without a family doctor, forcing many to rely on emergency rooms for health care.

Progressive Conservative Brad Johns, who is running in Sackville-Beaver Bank, said Liberal Premier Stephen McNeil broke his promise of a doctor for every Nova Scotian and that's leading to crowded ERs at hospitals and health-care centres, like the Cobequid Community Health Centre.

But McNeil said Tory Leader Jamie Baillie is trying to "scare people," and that short-term fixes won't solve the health-care delivery problem.

Dave Wilson, the NDP candidate for Sackville-Cobequid, said his party is the only one that will address the "crisis" in health care.

The Liberal candidate in Dartmouth North, Joanne Bernard, said Thursday the Conservatives are focusing on business tax cuts.

"The Conservative party has no funding for youth jobs and their platform calls for $500 million in cuts," Bernard said in a release.