The St Nicholas Building, which stands opposite St Nicholas Cathedral, is due to undergo a range of improvement works in a bid to make it one of the most attractive grade A office spaces in the city centre.
The building currently comprises 64,175 sq ft of office accommodation behind a grade II-listed façade.
A range of tenants occupy space over five floors including Randstad, Nathaniel Lichfield and Partners, and the National Audit Office.
Naylors was appointed as managing agent of the St Nicholas Building in June 2015 following its acquisition by a private investor and the firm's office agency department is working alongside Lambert Smith Hampton as letting agents for the building.
Dean Clark, associate director at Naylors, said: "The project will see major investment made in the common areas including new lifts and full refurbishment of the lift lobbies and toilets. We are also carrying out re-modelling works to vacant suites to help accommodate new tenants.
"Works are already underway and we expect completion of the project by the end of May with the new lifts to be installed later in the year."
Simon Taylor, director and head of office agency at Naylors, added: "There is an absence of top quality office space in the city centre so this investment in St Nicholas Building is perfectly timed.
"Within the past few weeks we have completed the letting of over 8,000 sq ft to Sir Robert McAlpine. We are also in advanced discussions with interested parties regarding further suites and hope to be announcing more lettings within the coming months."