A massive new Collins Street tower could cast a shadow over the Yarra River and Southbank.

Planning Minister Matthew Guy has notified Melbourne City Council he intends to ease planning restrictions that prohibit shadowing of the Yarra River to allow a development at 555 Collins Street.

Matthew Guy has notified the council he intends to ease planning restrictions that prohibit shadowing of the Yarra River. Credit:Luis Enrique Ascui

The site is owned by the Stamoulis Property Group and some at the council have estimated the new tower could be one of Melbourne's tallest buildings.

One councillor estimated the shadow could stretch out towards City Road.