Figures obtained by the Green Party through Greater London Authority (GLA) suggest that current regeneration schemes will result in the loss of 1,094 "social rented" homes in the borough.
Regeneration schemes are the redevelopment of homes owned by the council or housing associations that have been approved but not yet built.
But the council hit back at the Green Party, which used the information to describe regeneration as a "disaster", by arguing the figures do not indicate that units will decrease due to an increase in larger homes.
A council spokesperson said: "Claims that Ealing’s regeneration projects lead to a reduction in the availability affordable (including social rented) housing are incorrect and misleading.
"Where fewer one and two bedroom units are being built this is because more family-sized homes are needed to alleviate overcrowding and accommodate the needs of local families.
"In all instances, enough new homes are being provided to accommodate existing tenants who wish to remain in their local area.
"The whole purpose of our estate regeneration schemes are to replace existing poor quality social housing with new better quality homes for the existing residents at the same rental levels."
Regeneration 'a complete disaster'
The figures only include regeneration schemes that involve the replacement of 15 or more units, approved before January 14 this year.
Among the regeneration projects are developments at South Acton Estate, St Bernard's Hospital, Rectory Park Estate, Golf Links Estate, Copley Close Estate, Green Man Lane Estate and Havelock Estate.
Also included is Sherwood Close Estate, land At R/Of 45-55 & 53 Brigstock Road, land at Dickens Yard & Church 2-12, New Broadway, Cromer Court, Lytham Court, St Davids Court, Dormers Rise/Whitecote Road and 24 Creswick Road.
London Assembly Green Party manager Darren Johnson said: "Under the cover of tired stereotypes about sink estates, the Mayor is whittling away at homes that are genuinely affordable to Londoners.
"He then tries to deceive by talking about new homes being built, without mentioning all those he is knocking down.
"With a few exceptions, estate regeneration has been a complete disaster in London and has made our housing crisis worse."
But a spokesperson for the Mayor of London hit back at the Green Party and said that by only focusing on homes which haven't been built yet, key information about affordable homes had been left out.
The spokesperson added: "These figures are misleading because they only take into account the affordable homes replaced within the new development, ignoring those that are delivered off site as a direct result of estate regeneration.
"By only looking at the pipeline, they also ignore all the homes that have already been delivered - earlier phases tend to prioritise the delivery of affordable homes ahead of market homes."