Children's Secretary Ed Balls said today that he believed headteachers would fulfil their "professional obligation" rather than go ahead with a boycott of next month's Sats exams.
Two teaching unions are conducting a ballot over the boycott of the national curriculum tests, which the Department for Children, Schools and Families has previously said would be unlawful.
Asked today whether the Government would take action to stop a boycott going ahead, Mr Balls said that, although headteachers were legally obliged to invigilate Sats, it was not "simply about legal obligations".
He said: "It's actually professionalism and dialogues.
"I think the more heads look at these issues, the more they'll see their professional obligation is to work with us to reform for the future and to make sure that children's learning isn't disrupted.
"I'm confident that, if people think hard about this in the next few weeks, that's where they'll end up.
"Because I trust in the professionalism of teachers and heads, I would rather talk dialogue.
"It would be a mistake to respond to some of the rhetoric we've heard in the last few days."
The National Union of Teachers and the National Association of Head Teachers want to see Sats replaced by teacher assessment and argue that the tests are bad for children, teachers and education, and cause unnecessary stress.
Speaking after his address to the NASUWT teaching union's annual conference in Birmingham, Mr Balls said: "I've said in the last few days we should talk about how we improve things for the future and I think the fundamental issue, if you look at the ballot words, is to look at accountability and how the results are used to judge schools.
"And that's what our Report Card reforms are all about."
The Government is introducing the School Report Card to give what it says will be a wider view of schools' achievement than the traditional league tables provide.
Sats tests in English and maths are due to be taken by around 600,000 11-year-olds in the week beginning 10 May - potentially less than a week after the country goes to the polls.
It means a boycott could be the first battle a new government - of whichever party - has to face.