DUBLIN CITY Council is meeting with building companies bidding for public-private housing schemes after the future of five such projects was thrown into doubt this week.

On Monday, the council announced that builders Michael McNamara and Company and Castlethorn would not be going ahead with five proposed schemes as changes in the housing market had made them "unviable".

However, McNamara subsequently told The Irish Times it had not pulled out of the projects. Instead it said it wrote to the council pointing out that changes to building regulations and apartment size requirements threatened the schemes' viability.

Yesterday, the council said it was meeting with all other public-private scheme bidders and has "begun the process of undertaking a risk assessment on each project". The council plans to report to next Monday night's meeting on the talks. There are four such schemes, involving 3,000 homes, currently in various stages of the bidding and planning processes.

The council has received a planning permission application in relation to one, involving 715 houses in Coolock.

Construction firm Rohcon bid for this. A company called ADN Developments submitted the planning application in December, and the council has since told it to provide more information.

It was not possible to establish yesterday whether permission has been sought for another project involving 800 units in Park West and bid for by building companies Durkan and Bennett. A further 1,000 homes are proposed for St Teresa's Gardens and Charlemont Street.

Under the public-private system, building companies bid to provide the council with social and affordable housing, and pay for this by taking a share of the units themselves and selling them on the open market.

However, building industry sources say the new regulations have increased costs and risks while cutting the number of homes that can be built.

They point out that the new rules have come into force since bidding opened for Dublin City's various public-private schemes.