HALIFAX -- Nova Scotia's Liberal government announced the rollout of a key election campaign promise to provide a free pre-primary program for four-year-olds across the province Tuesday, prompting critics to charge that it is acting in haste while undercutting existing non-profit providers.

Education Minister Zach Churchill said 30 new classrooms would be added to 20 existing classes beginning in September, meaning the play-based learning program would be offered in 50 classrooms at 43 locations across the province.

"We know based on evidence how important pre-primary programming is," said Churchill. "This is going to help our children transition into an academic learning environment, it will help them socialize in that environment, and we know that it will have outcomes that will impact their lives."

The plan is to have the program in place for all four-year-olds over the next four years at an estimated cost of $49.9 million a year. But Churchill said an additional $750,000 was needed to expand the program, boosting the initial estimated price tag in the first year to just over $4 million.

The program will operate during normal school hours for children who are at least four years of age by Dec. 31.

Churchill said the plan is to provide one early childhood educator for every 10 children in a class, with a maximum of 24 children per class.

"This number is based on a national norm for pre-primary programming that's available in schools, so that's the number we went with," Churchill said.

He added his department would also be discussing the ratios required of private daycare providers, which is currently set at one early childhood educator for every eight children in a class.

However, in a significant proviso Churchill said the availability of the service would be contingent on available staff. He said all of the promised classes would be in place by the last week of September if staffing levels are met.

"That is a challenge for us. Staffing is required to get these facilities up and running and so that's going to be our focus now is working with our school boards to get the appropriate staff hired."

Churchill also said individual school boards would determine salary levels for the new hires.

The announcement drew a derisive response from a member of the province's Non-Profit Directors Association.

Bobbi-Lynn Keating, who works at the Peter Green Hall Children's Centre in Halifax, said the province's plan was "insulting" to non-profit providers because it creates two sets of operating rules on such things as salaries and class ratios.

She said this comes after the province limited increases in parent fees to one per cent a year, while requiring that early childhood educators are paid a floor wage based on their level of qualification -- $15 an hour for level 1, $17 an hour for level 2 and $19 an hour for level 3.

"It's an impossible situation when you're non-profit," she said. "They are telling you what you can charge and what you have to pay -- the numbers don't equal out."

Keating also expressed doubts the province would be able to hire the numbers of qualified professionals needed to meet its timeline on the program rollout.

"We can't get trained early childhood educators now," Keating said. "Even if they pay them more, there's nobody out there."

Progressive Conservative education critic Tim Halman said it all smacked of planning on the fly.

"They aren't laying concrete plans . . . there has to be more substance to this," he said.

But Churchill cautioned the program is in the early stages of what will be an evolving four-year rollout.

"This is subject to change depending on how the conversations go with school boards," he said. "Also we will be moving forward with a robust consultation with parents as well as the current early learning providers."

The department said parents could pre-register their children immediately online at www.ednet.ns.ca/pre-primary or by calling 1-833-424-2084.