The housing executive may have to allow half of its 86,500 homes to fall into disrepair from 2020 if it cannot secure additional funding, according to a senior civil servant.
The suggestion is in a letter written by Department for Communities (DfC) permanent secretary Leo O'Reilly.
The letter, which was sent to North Antrim MLA Mervyn Storey, was seen by investigative news website The Detail.
The NIHE told The Detail the plan was the "worst-case scenario".
The letter stated that the housing executive is to begin planning "for the longer-term decommissioning" of more than 43,000 properties from the start of next year if a solution cannot be found to plug an estimated £140m annual budgetary shortfall.
This would allow it to prioritise the maintenance of the remainder of its homes.
However, there are fears it would put pressure on housing waiting lists and increase homelessness.
According to the NIHE's latest annual report, of the 36,198 applicants on a waiting list for a home in Northern Ireland in March:
- 24,148 were considered to be in priority need of housing
- 11,877 were deemed to be homeless
NIHE's financial difficulties are being blamed on low rental income, a repair backlog and debt and management costs.
The 6 August letter from Mr O'Reilly, which was sent to Mr Storey, a DUP MLA, outlined a number of potential solutions, all of which would need legislation to be passed.
It warned that "stock continues to deteriorate due to lack of investment".
The letter added: "The NIHE has sought to manage this position through a process of focusing on essential maintenance of its properties while curtailing the longer-term maintenance that is essential to ensure the longer-term availability of the housing stock.
"Towards the end of 2017, the NIHE estimated that if by 2020 there was no prospect of the future investment that reform may secure, then the organisation would have to start de-investing in approximately half of its portfolio in order to provide a sustainable future to the other half."
"The Housing Executive will start planning for this from the start of 2019.
"It will be a plan involving difficult decisions from the board of the Housing Executive as it seeks to prioritise the maintenance of part of its stock while planning for the longer-term decommissioning of the rest of its stock."
An NIHE spokesman told The Detail: "Options that could be explored would be the possible sale of homes to the private sector, transfer to housing associations, or demolition and redevelopment.
"While in some cases this may be feasible, it is our experience that there would be a great of deal of difficulty in getting agreement from tenants, local communities and political representatives to the transfer of stock.
"The Housing Executive, as would others, has also major concerns about the significant loss of stock and the detrimental impact on meeting increasing social housing need in Northern Ireland."
Mr Storey was social development minister between September 2014 and January 2016.
He told The Detail he raised the problems facing the Housing Executive with former First Minister Peter Robinson and former Deputy First Minister Martin McGuinness more than two years ago when he was the minister responsible for housing at Stormont.
"Everybody has known these problems have been there but there has been a failure to grasp the reality of the situation and find a workable solution," he said.