This means that some children will receive nearly a year's extra education.
Drake First School in Thetford, Norfolk, has lost 14 pupils this year because of neighbouring schools' policies of admitting younger four-year-olds full-time. A total of 17 schools in the county have changed their admission policy to cash in on the voucher scheme.
In Kingston, Surrey, parents at Coombe Hill infants school are upset at plans to open a nursery class because four-year-olds who get a place will not be guaranteed a place at the school, while the other four-year-olds in the Coombe Hill reception class are guaranteed a place.
And in Shropshire education officials are promoting partnerships with the voluntary sector. The authority is anxious to avoid the early admission of four-year-olds into reception classes - a practice which has long been criticised by early-years experts but which is increasing with the introduction of vouchers.
Some authorities are considering standardising their admission policies but in other areas the scramble appears to be turning into a free-for-all - a race to attract maximum voucher income by cramming as many four-year-olds as possible into reception.
The trend towards admitting children to school younger predates the Government's nursery voucher initiative but, with the national implementation of the scheme only five months away, all local education authorities and schools are having to rethink.
Schools minister Robin Squire was sympathetic to the increasingly blurred line between reception class and playgroup last week when he spoke at the opening of the Nursery World exhibition in London: "Some playgroups are concerned that local schools will expand their reception class to cater for younger four-year-olds. But a reception class is not necessarily the most appropriate setting for a child who may have just turned four.
"It may be that another type of setting, with a more favourable child:adult ratio, and a different kind of regime is more appropriate. It is for parents to make the best decision for their child."
But Mr Squire may be simplifying the issue. Not only are many parents confused about the voucher scheme but a substantial number believe they have no choice but to snap up the increasing number of reception class places to secure a place in the school.
Among the eight education authorities contacted by The TES, Devon is the only one proposing a standard admissions policy, although Hertfordshire is consulting parents and schools about a single admissions system. Devon proposes a staggered intake to help schools cope with the 6,000 four-year-olds who would start school two terms before their fifth birthday rather than one term before as at present, and local variations to suit schools' circumstances for the first year of the voucher scheme.
The county has joined forces with private and voluntary groups and the Diocesan Boards of Education to plan the voucher scheme implementation in Devon.
Shropshire has also adopted the partnership route. It is currently consulting headteachers and school governors about expanding education for four-year-olds through local partnerships. Unlike many authorities, it is also planning its expansion through nursery classes as opposed to reception classes.
Carol Adams, county education officer for Shropshire, said: "We are keen to implement vouchers in partnership with the voluntary sector, rather than at its expense. We are aiming to avoid the early admission of four-year-olds into reception classes. Most authorities appear to be going for early admission to schools at the expense of playgroups and I think we are the exception. We are also very interested in working in partnership with the private sector. "
This would be music to the ears of Cora Mullenger, chairman of Marsham Playgroup in Norfolk. She believes that schools' decisions to set up nursery units to cash in on the voucher scheme have been "disastrous".
"Some playgroups are considering closure because of the reduced numbers of children and some playgroups have already closed ... If playgroups close then where do the three-year-olds go? They may lose out completely and the nursery providers will have the task of introducing them to the basic building blocks of life one to two years too late."
A similar problem is developing in Hertfordshire where the LEA is planning to give all parents of four-year-olds the opportunity of a free part-time nursery place.
The private but non-profit-making Summercroft Nursery Group, which has been operating successfully in a Bishop's Stortford infant school premises for 15 years was told to leave so the county could set up its own nursery unit.
But after a protest by parents, the council has agreed to consider a service level agreement which would involve Hertfordshire buying services from the nursery group.