The West Midlands Regional Assembly is likely to cross swords with the government over housing provision in the area.
The region has just drafted its second phase of revisions to allow for 365,000 new homes to be built on brownfield sites, particularly in the major urban areas of Birmingham, the Black Country, Coventry and the north Staffordshire conurbation.
However, the Department for Communities and Local Government (DCLG) wants to see 420,000 new homes built, sparking local fears of more development on rural greenfield land.
Communities Minister Baroness Andrew wrote a letter to the regional assembly querying the plans set out in the Regional Spatial Strategy.
She said: 'We do not wish to fundamentally question the Spatial Strategy for the region, but we are concerned that the very rigid application of some of the principles may be unnecessarily constraining longer-term development.'
But the regional assembly believes its plans are ambitious enough for the area.
Councillor Rex Roberts, chair of the assembly's regional planning partnership, said: 'While we recognise the need to improve housing affordability, it is important that we do not fall into the trap of a simple numbers game.
'This could lead to the worst of all worlds if more greenfield sites are released and efforts to regenerate brownfield land and derelict sites are diverted.'