The Government has agreed to pay for 550 extra social housing units in Dublin's Poolbeg West development of 3,500 new homes.

Developers are only required to provide 10% or 350 homes for social housing but under pressure from councillors a deal has been agreed that will see just over 25% provided to those on the housing list and those on lower incomes.

A total of 900 homes will now be provided as social and affordable housing including units for senior citizens.

A cross party motion supporting the deal from Labour, Fine Gael, Fianna Fáil, Green and some independents referred to a "commercial agreement" between the council, the Department of Housing and the owners and developers to increase the social provision.

This would be in return for "confirmed funding" from the government and the provision of infrastructure such as the planned bridge over the mouth of the Dodder and an extra cycle and pedestrian bridge beside the Tom Clarke bridge.

The motion was carried by 41 for to 6 against.

Sinn Féin had put down an amendment asking for an extra 100 homes for senior citizens.

But Chief Executive Owen Keegan said 900 was as much as could be achieved and any extra demand would lead to appeal by the receivers to An Bord Pleanála and that could result in the bare minimum 10% social provision.

The Sinn Féin motion was defeated by 20 votes in favour to 28 against.

The lands earmarked for housing are situated on the Glass Bottle and Fabrizia sites which cover 15 hectares.

Of this 80% will be zoned for residential development with the remainder for commercial acting as a buffer between the new homes and industrial sites.

The loans on the lands were taken over by NAMA and their ownership is currently in receivership.

Councillors voted to decrease the amount of one bed units from 25 to 30% to 20 to 25%, while the amount of three beds will be increased from 15 to 20%.

A quarter of the one beds will be allowed to be studio apartments while there will be up to 300 build to let units and also student accommodation.

The Strategic Development Zone (SDZ) plan which cannot be appealed once approved by An Bord Pleanála involves blocks of apartments mainly four to seven stories high but eight will be up to 14 and one up to 16 stories.