The records are being moved to new headquarters
People seeking access to public records in Northern Ireland are being warned that a move to a new office will affect the service from next year.
The Public Record Office is moving to headquarters in Belfast's Titanic Quarter in May/June 2011.
As the records are being collected and moved between September 2010 and May 2011, they will be not be available for physical access.
However, it is hoped more of them will be made available online.
The Department of Culture. Arts and Leisure said it was letting people know well in advance because many of those who come to the office to access records are from overseas.
A limited correspondence and telephone enquiry service will remain to address freedom of information queries and urgent legal enquiries.
Culture Minister Nelson McCausland said moving the records was a "mammoth task".
"Access to public records is a core function of the Department and to minimise disruption to customers, PRONI is increasing the amount and range of material which will be available online," he said.
"Discussions are also taking place with partner organisations to make arrangements to allow customers to have alternative sources to draw upon during this time."