Plans for the London 2012 International Broadcast Centre (IBC) and Main Press Centre (MPC) have been labelled as 'extremely weak' by the government's advisory body on urban design and architecture.

The Commission for Architecture and the Built Environment (CABE) also suggested that the proposed designs for the media complex could 'blight' the Olympic Delivery Authority's bid to deliver a strong, lasting legacy from the Games. According to CABE's London 2012 panel, both the 'extraordinary banality' of the IBC and the 'large monolithic block' that will become the MPC have raised serious concerns about the new facilities, which have been designed by RPS Group and Allies and Morrison respectively.

Paul Finch, chair of the London 2012 design review panel, said: "Unless there is a fundamental rethink, then people could be forgiven for wondering why sheds have been removed from the Lower Lea Valley in the name of high quality urban regeneration, only to be reinstated at a much larger scale. "When we talk about poor architecture we are not just talking about style here. We mean identity and character, and scale and coherence, and the creation of a legacy which is appropriate to a site of this importance."

If detailed designs for the IBC and MPC are given the green light – a decision which is expected on 9 June – CABE is urging planners to ensure that it comes with the condition that the architectural quality is improved.