Mick Brookes, general secretary of the National Association of Head Teachers, said he would not rule out a boycott of key stage 2 tests. He plans to meet other teachers' unions to discuss action.
Members of the NAHT - which represents more than 85 per cent of primary and 40 per cent of secondary heads - meet in Harrogate today for their annual conference.
In his first conference speech as leader, Mr Brookes will urge heads to "mobilise parents and governors in a true demonstration of parent power".
Mr Brookes wants the coalition to oppose KS2 league tables and the compulsory introduction of extended services - such as after-school clubs - if heads do not have the money for them.
Until last year Mr Brookes was headteacher of Sherwood junior in Nottinghamshire.
He refused to set the tests in 1993, when they were introduced, and made the school's results invalid the following year by hinting to parents that their children might want to arrive late.
He said: "The tests are grossly damaging and give a false picture of schools."
Mr Brookes says the Government needs to have a national picture of 11-year-olds' attainments and he is investigating how this can be achieve without putting undue pressure on children.
Boycotts of national tests by teachers in the early 1990s led to Lord Dearing's review which scaled down the national curriculum. A bid by the National Union of Teachers to boycott tests in primaries in 2004 failed after fewer than a third of members backed it.
The NAHT is already at loggerheads with the Government after pulling out of the social partnership between ministers, unions and employers. Members voted to quit due to underfunding of the workload agreement.
Mr Brookes said ministers were losing contact with primaries because they were unwilling to work with his association and the National Union of Teachers, which did not sign the agreement.
"We do not want to antagonise the Government but it needs a wake-up call,"
he said. "We need a relationship that is adult-to-adult, not parent-to-child where ministers say 'You're very naughty'. That is only going to make our position more entrenched."
Margaret Morrissey, National Confederation of Parent Teacher Associations spokeswoman, said: "Parents would be delighted if they (tests for 11-year-olds) were abolished. You only need to look at Wales where the pupils seem happier but there is no evidence that standards have dropped."
A straw poll of more than a dozen primary heads by The TES found the majority wanted the league tables abolished, though several feared legal challenges if they boycotted tests.
All six main teachers' unions signed a joint statement last year calling for the abolition of KS2 league tables and for tests for that age group to be reviewed.
This weekend's NAHT's conference is expected to be dominated by concerns that inspections and government initiatives have given headteachers excessive workloads and pressures of the job are causing heads to quit.
News 16, Leader 22 Leadership 27