The owners of the David Maddison Building have lodged plans for an addition to the Newcastle landmark.
Developer Stronach plans to convert the inside of one of the King Street building's distinctive quadrant towers from a lecture theatre to office space and attach a three-storey annex.
The 1981 building was designed by prominent architect Lawrence Nield, who is now head of the Heritage Council of NSW.
It was home to the Hunter Medical Research Institute before being converted to commercial space in 2012.
The Stronach project adds almost 1000 square metres of office space to the building but not more car parking.
The development application argues the office conversion will generate less traffic than the auditorium.