Education Secretary Nicky Morgan has defended plans for more "robust and rigorous" tests for seven-year-olds, insisting it was up to parents and schools to "manage" the pressure on children.
Teaching unions warned proposals to rethink Key Stage One tests in England - which could see a return to nationally standardised marking - were "educationally harmful" and would damage pupils.
However Mrs Morgan insisted tests should be seen as a normal part of school life and she urged parents not to build up expectations around them by staging events like "after test parties".
"They are not exams, they are tests. There are ways for schools and parents to manage that," she told an event staged by the Policy Exchange think-tank.
"When my son did his Key Stage One tests he didn't know he'd taken them until afterwards.
"It's the same when we get to the end of primary. I don't want to see after-test parties being held. I want it to be something that children take as part of their schooling."
However Kevin Courtney, deputy general secretary of the National Union of Teachers, said ministers were turning schools into "exam factories" in a way that was "educationally harmful, unreliable, costly and damaging to children".
"The UK already has the most excessively tested children in the whole of Europe," he said. "Children and young people urgently need the formal assessment burden on them reduced."
Dr Mary Bousted, general secretary of the Association of Teachers and Lecturers, said changes to testing would not improve standards of maths or English.
"We support the Government's commitments to help schools enable more children to achieve expected standards of English and maths at primary school," she said.
"But continual testing is not the answer and nor is changing the goalposts every time a minister speaks."
However, Mrs Morgan insisted the tests were necessary to ensure children were being taught the "basics" in primary school, otherwise the rest of their education would be "a game of catch-up".
In what was billed as her first major policy speech since the election, she also confirmed the creation of a new National Teaching Service to recruit 1,500 of the "brightest and best" teachers by 2020 to work in the toughest schools.
She also set a new target for 90% of secondary school pupils to study the core subjects of English, maths, science, history or geography and a language at GCSE - the subjects included in the English Baccalaureate performance measure. Currently the figure is around 39%.
While some headteachers are against the move, arguing it would not suit every pupil and could mean less time for more creative subjects, Mrs Morgan denied she was pursuing an "old-fashioned, outdated, atavistic view" of young people.
"I don't care if young people choose to watch Gogglebox and the X-Factor; or if they're entranced and absorbed by YouTube and Buzzfeed," she said.
"But I do care if they've never been given the chance to read Shakespeare or study Darwin, to perform on a stage or to fiddle with a Raspberry Pi. It's that choice that we're trying to achieve."