The union, which has 100 members at the housing association, said 84 per cent of them voted in favour of industrial action in a ballot held yesterday and that strikes would take place from mid-June.
One Housing Group is a charitable industrial and provident society and is considered an exempt charity by the Charity Commission because it is regulated by the Financial Services Authority. It employs 1,000 people.
One Housing said salaries would be "market linked" from February next year, which will mean pay cuts for some staff. It said 75 per cent of its employees had agreed to the changes in a consultation.
But Unite said the pay cuts would hit 200 staff members with pay cuts of up to £8,000 a year and an average of £2,000 for most of those affected.
Unite also criticised the housing association for increasing the salary of Mike Sweeney, its chief executive, by £31,000 in pay and bonuses to £176,000 a year.
"OHG has been awarded dozens of contracts by local authorities worth millions, the bulk of which cover workers’ wages," said Nicky Marcus, regional officer at Unite. "If management cut wages mid-contract, or at the beginning of the contract, the question for councils, commissioners and council taxpayers must be: ‘Where is that money going?’
"Management's assertion is that because a few housing associations pay less than OHG, wages should slide downwards to meet the lowest common denominator. But they never apply the same logic to themselves: rather, they say ‘managers and chief executives out there are paid more than us so our wages must rise accordingly’."
A spokeswoman for the housing association said it was disappointed at the strike decision but that services would be unaffected because of the number of people involved.
"Our salary transformation process affects only staff who are being paid above market rates," she said, in response to Unite’s criticism of Sweeney’s salary increase.
"Our success in winning new contracts is due to the recognised premium quality of services that we deliver. We know our approach is working, having both underwritten plans for investment in a large programme of new build supported housing and seen a number of high-profile tender successes in retaining existing business in a sustainable way."