Thousands of youngsters are being denied the chance to swim for free after three local councils failed to sign up to a scheme to scrap entrance fees to pools for children.

North Somerset, South Gloucestershire and Bath and North East Somerset have agreed to waive charges for pensioners but refused to do the same for under-16s, despite being offered Government cash to help fund the scheme.

They claim the money available would not cover the cost but Communities Secretary Hazel Blears insisted the shortfall would be minimal.

She said the councils were "denying residents the chance to swim for free", adding: "It is a shame some Tory councils are so short-sighted that they are failing to take advantage of this money."

Bristol will offer free swimming to both groups.

The Government wants to encourage people to boost their fitness under the Swimming Challenge Fund and more than 20 million over 60s and under 16s are expected to benefit.

Over two years, £140 million will be handed out from central government to local authorities, which officials said would cover "the majority" of the councils costs when launched in April.

The Labour Party pointed out all of the 52 eligible local authorities not taking part in any part of the scheme – 18 per cent of councils in England – were Conservative controlled.

Councillor Terry Gazzard, Bath and North East Somerset Council cabinet member in charge of leisure, said: "The Government has provided some funding for the council to introduce free swimming for the over-60s for two years, and Bath and North East Somerset Primary Care Trust has in principle agreed to help plug the gap in Government funding for this.

"However, the proposed Government funding was not sufficient to cover the costs of free swimming for under-16s.

"If the Government increases its funding offer, we would be in a position to consider this decision again.

"With many schemes like this, such as free bus passes and library internet use, the Government frequently provides either insufficient or temporary funding, meaning already-stretched local councils have to try and fill the hole."

A South Gloucestershire Council spokesman said: "We have signed up to take part in the scheme to offer free swimming to the over 60s as the funding from the Government will cover the cost of this initiative.

"We explored the option of providing this for under 16s with our partners who provide swimming in the area, but unfortunately the funding from the Government would have covered less than half of the cost and we are not in a position to fund the remainder.

"We have contacted the Government and asked if they can reconsider their funding criteria to provide a free swimming programme for under 16s."

Stephen Makin, media spokesman for North Somerset Council, said: "We will be offering free swimming to the over 60s.

"For the under 16s we are still discussing with the Government about a proposition we have put to them and we need clarification from them whether this is acceptable before agreeing to the scheme.

"So we have not ruled ourselves out, but the condition for our participation is that it would have to be fully funded."