The proposals - on Old Hall Street - will bring an additional 13,000m 2of new office space to the city.
The masterplan of St Paul's Square, for the English Cities Fund, consists of three commercial buildings, a residential apartment complex, a 400-space car park and a new public space.
RHWL's designs have won the backing of the local development agency Liverpool Vision. Jim Gill, chief executive, said: 'The success of St Paul's Square demonstrates the confidence developers now have in Liverpool city centre.
'This scheme is the first phase of our proposals to create a new business district in the city centre, and it is very encouraging to see such rapid progress.'