Regulatory body the Housing Corporation wants Ujima Housing Association, which has run into severe financial difficulties, to be taken over by housing giant London & Quadrant.
But the takeover plans have caused a backlash from black community groups.
The former head of the Commission for Racial Equality, Lord Herman Ouseley, is leading the Save Ujima campaign. He has appointed TK Associates to direct the campaign to save the London association.
The agency plans to lobby the Government, London authorities and The Housing Corporation. It also aims to ramp up media coverage by targeting London-focused press, radio and TV stations, ethnic titles and housing press.
TK Associates director Tariz Khwaja said: 'It is an urgent issue and will be a short-term campaign. Ujima is on the brink of closure and we must act quickly.'
Lord Ouseley said: 'We're appalled by this attack from the Housing Corporation and the way the housing minister is sitting back while it's all being forced through.
'The merger will destroy this unique organisation and everything it has worked so hard to build up over the past 30 years. This is not what we expect from a Government that says it's committed to social inclusion.'
Housing Corporation press officer Sandra White insisted: 'Our priority at all times has been to ensure that the interests of tenants, taxpayers and lenders are safeguarded.'