Bristol City Council is set to spend £1 million on a temporary solution to the city's primary places crisis.

But it still does not know where it will provide the extra reception classes.

Talks are continuing with a number of schools to try to secure 250 more places in areas of need before a fresh round of offers is made towards the end of next month – but some schools have already said they are unable to help.

The number of families still waiting to hear where their four-year-olds will go to school in September is now more than 500 – and rising.

That number includes the 278 parents who were not allocated a place at any school, despite applying before the council's October deadline, as well as an official figure of 244 late applicants.

The Bristol Post understands that since the last official count, about 200 further late applications have been received. Last year the final total of late applications reached about 600.

However, many of the late applicants are likely to be in the south of the city, where by and large there is not a shortage of school places.

A report to councillors outlines the extent of the problem in the north and east central areas, the actions being taken to find the best short-term solution, and the lessons that must be learned.

The document from service director Kate Campion reveals that a review of the council's admissions services will be undertaken during the summer term.

It says officers knew last year that additional places would be required for September 2009 and concedes: "The programme to investigate options for temporary expansions should have been established at an earlier stage and should have been pursued with more vigour."

After the crisis was revealed in February, the then Labour administration at the city council announced that it was in discussions with eight schools – Little Mead, Henleaze Infants, Hannah More, Millpond, Cabot, Sefton Park, St Barnabas and Glenfrome – about putting in extra classes.

But it later emerged that the first some of those schools heard of this was when they read it in the Bristol Post and governors of some have already rejected the idea.

The report to next Monday's meeting of the children's services scrutiny commission points out that temporary expansion of schools can be tricky because extra buildings restrict play space, while "bulge" classes in schools that will not be expanded permanently can also create problems.

Ms Campion also reveals inadequacies in the methods used by the council to predict the number of reception places needed.

Her report explains that forecasts based on birth data, GP registration date and projected population figures had produced conflicting and unreliable results.

"One clear lesson is that capital planning, school organisation and school admissions policy-making need to have much more robust links and a clear framework for joint decision making," the report says.

Clare Campion-Smith, Lib Dem cabinet member for schools since the party took control of the council a month ago, in a separate report to the scrutiny commission, said resolving the primary places crisis was a key priority for the new administration.

She and Lib Dem leader Barbara Janke invited the 278 parents not allocated a place in the first admissions round to a meeting last week, where they apologised unreservedly.

After that meeting, Mrs Campion-Smith said: "A lot of suggestions were made which will be considered. To take this forward we will be placing more information online when it becomes available and will continue this dialogue to ensure that we find the best solution at this late stage for children needing a primary school place for September 2009.

"That is our immediate priority but we have to be thinking ahead and making sure that short term solutions match with longer term sustainable solutions. The stress caused to parents was very clear – we must avoid this in the future."