HALIFAX -- Nova Scotia's premier says "decades" of education-policy errors -- including his own miscues -- contributed to Friday's historic teachers walkout that saw the legislature enveloped in a cacophony of protest speeches and cowbells.

The province's schools were closed Friday as the Nova Scotia Teachers Union held a one-day strike while the Liberal government pushed through a law imposing a four-year contract.

Amidst ringing house bells, Premier Stephen McNeil gave interviews in his office, acknowledging he may have failed to properly hear teachers' message through the years.

"Obviously the investment and impact we've put into classrooms hasn't hit the mark," he said, as the protest speeches continued metres away outside.

A Education Department spokeswoman says it has invested almost $59 million since 2013 on measures that include the hiring of 59 math mentors and 114 reading recovery teachers, the reduction of class sizes in elementary schools, and the addition of math and literacy supports. The province says it has also "engaged with teachers to streamline the curriculum" in elementary school.

But teachers testified before a legislature committee on Thursday about being overwhelmed because of a lack of resources for students with behavioural and mental health issues, and struggling in inclusive classrooms where there's not enough staff to assist pupils with learning disabilities.

"We need to listen to teachers about investments we need to make in classrooms. The one place I was investing in every (provincial) budget was in classrooms. And obviously it didn't work. The frustration here is real," said McNeil.

Outside, the leader of the teachers union said the difficulty with McNeil's stated sympathies is that they can't trust his imposed remedies -- a distrust deepened by back-to-work legislation her lawyers will challenge as unconstitutional.

Promises of more money in the future for resource teachers, children with learning disabilities and smaller classes are more likely if they're actually part of a deal, argues union president Liette Doucet.

"At this point we haven't seen any changes made by this government, so we've attempted to put them in the contract so we can ensure they happen," she said.

Sherry Johnston Sperry, a high school family studies teacher participating in her first strike, described how trying working conditions lie at the heart of the dispute.

In one year she has had up to 15 students with so-called individual program plans that require more attention, and classes with 30 students. She said that means she cannot provide students with the proper attention, even working extra hours.

"I have two young children and I feel I'm either neglecting them or my students," she said. "I struggle with that and it's gotten a lot worse over the last five years."

McNeil said he wants to hear the details of these problems through a council the legislation will create to look into classroom conditions and spend $20 million on improvements.

But the details of his legislation on the council are themselves provoking union frustrations.

In earlier versions of the council -- contained in one of three offers voted down by the 9,300-member union -- the body was co-chaired by the union and allowed for disagreements over how money would be spent to go to an arbitrator.

In the latest contract before the legislature, there are nine teacher members being appointed by school boards and no arbitration process for disputes on spending the money. The NDP is proposing an amendment to return arbitration to the process.

"It was meant to be both sides working together to make the changes. This (legislated version) is meant to be something completely different," said Doucet.

McNeil defended the committee, and said it will allow his government to hear more directly from teachers.

"That amount of money was put on ... as a show of good faith. It's certainly not the end of the amount of money required to invest in education," he said.

He also said recommendations from a committee that will examine ways to improve education for students with learning disabilities will not be shelved.

"If we're going to make policy changes, of course there's going to be money. We'll make those funding changes to it."

The premier may very well have to make a direct pitch to voters over his handling of the teachers and public sector unions, noting how the Liberals have balanced the budget for future generations.

The contract offered to the teachers contains a three per cent salary increase over four years, setting a pattern for upcoming talks with other public sector unions that will help McNeil's government stay in the black.

Doucet said during a speech on Friday that her union will martial its forces to ensure McNeil pays a political price.

"We will make sure this is never forgotten. An election is coming," she said.

The legislature was recessed on Friday afternoon, and McNeil was whisked away in a dark-windowed police car past the protesters.

It's expected the politicians will reconvene for final reading of the bill -- including possible amendments -- just after midnight on Tuesday.