Newhaven Library will open later than expected, with the building due to be ready in autumn.
The 1.6m facility was meant to be ready at the end of 2013.
Seaford’s £6m library building, which includes a library, cafe and supported living flats for adults with learning disabilities, will be open for business this summer.
A county council spokesman said: “We have now completed the preparatory work on Newhaven Library and will soon begin refurbishment work for the new facility.
“The preparatory work included stripping out the interior and a programme of asbestos removal.
“While we had hoped to open the library by the end of 2013, with any construction programme there is always the possibility of delays as work progresses.”
Newhaven Library in the High Street will hold a wider range of community events and activities. It will occupy the building which formerly housed clothing retailer M&Co.
The county council said once the ground floor library was completed, the next phase of the project involves working with potential partners to create a community hub for Newhaven using the first floor of the building.
Building on Seaford Library in Sutton Park Road began in October 2012
The scheme will support a new service to offer more direct access to resources in the community for older people with dementia or other mental health problems who have been assessed as needing support to help them live independently.
A county council spokesperson said: “The majority of construction work at Seaford Library has been completed, internal finishes have commenced and external works will follow shortly.
“We expect the building to be handed from the contractor in late spring, following which installation of library fittings will take place.
“The completion of both libraries will create state-of-the-art facilities offering a clean, modern environment, and will help to regenerate both towns.”
Artworks are proposed for both libraries, with funding coming from the Arts Council.
At Seaford the county council has funding for a bench, while at Newhaven it will create a window looking out on to the bus stop.