The social security office in the Old Customs House on the quay in Castletown is to close at the end of this month.
The Department of Social Care is also reducing the opening hours of its office in Ramsey.
It will no longer be open on Thursdays.
Social Care Minister Chris Robertshaw MHK said: ‘The Castletown social security office was opened many years ago when all benefits were paid there in cash.
‘Many of the services which used to be provided at social security offices can now be provided over the phone or on the internet while benefit payments are now made either into customers’ bank accounts or paid at post offices.
‘Consequently, there has been a significant decline in the usage of the Castletown office such that I can no longer justify the expense of keeping it open. Also the building itself is an old, listed building which is no longer fit for our purposes and requires significant investment. As a result, I believe that its closure and disposal will save money while not significantly affecting our services to the people of the south of the island.’
The department will continue to operate its office in Port Erin.
Jobseekers who currently sign on in Castletown will in future have the option to sign on either at the Port Erin office or at Markwell House in Douglas. From week beginning October 1 the Port Erin office will be open on Tuesdays and Thursdays (previously it was open on Mondays and Friday afternoons).
The closure for lunch at both the Ramsey and Port Erin offices is being reduced from one hour and 15 minutes to 45 minutes and the offices will close half an hour earlier at 4.30pm and 4pm on a Friday