Network Rail has been accused of cutting corners on the after scaling back plans for the second time this year.
The latest furore surrounds a revised planning application to retain and extend the old Navigation Street footbridge over tracks and platforms on the northern side of the station.
The bridge was initially due to be replaced and clad in the curved mirror-effect stainless steel canopy which dominates the rest of the new station design.
It was revealed earlier this year that globally from the New Street Gateway project over changes to the original design for the station鈥檚 atrium.
But while a change in material on the atrium may go unnoticed when the station opens next year, the footbridge is a major feature on the Navigation Street elevation 鈥 leading to criticism from city architecture experts.
Architect and said: 鈥淭his follows the rather unfortunate debacle of the original architect not completing the atrium.
鈥淭hat seemed to escape proper public scrutiny on a project which is supposed to delight over 30 million passengers and shoppers a year.
鈥淚f serious changes are being made now to the external appearance too, we really should be told on what grounds. Is it about making savings and dumbing down the essence of a great idea?
鈥淭his should go before the Birmingham City Council planning committee and the people of Birmingham should have a chance to comment on this change. We should be proud of the place, not apologising for it.鈥
Network Rail has asked for permission to retain the footbridge saying that extensive works could delay the completion of the station by months or lead to the closure of the track for a period.
An application has been submitted to the city council鈥檚 planning department and is out for public consultation until May 22.
On his Birmingham Central blog, regeneration blogger Simon Felton said: 鈥淚 find these proposals a little disheartening against the exciting vision we saw in the original design.
鈥淲hether, if this application is approved, visitors and future residents will wonder why they didn鈥檛 finish the plan is a question only hindsight and time will tell.鈥
Network Rail has stated that the installation of extensive stainless steel cladding over an operational railway is 鈥渋mpractical鈥 鈥 given that work could only take place for a few hours at night.
A Network Rail spokesman said: 鈥淏irmingham City Council鈥檚 planning committee is currently looking at amended designs for the Navigation Street footbridge.
鈥淭he footbridge was not part of the original planning application in 2006, but was added in 2009 and it is this design which has been altered to avoid adding months onto the construction programme plus extended closures to the railway which would cause a large amount of disruption to the travelling public.
鈥淭he redevelopment of Birmingham New Street will give Birmingham a station fit for Britain鈥檚 second city and transform the passenger experience for the thousands of people who use New Street every day.鈥
The new plans were revealed in the week that Secretary of State for Transport Patrick McLoughlin visited to the construction site to check on progress.
Mr McLoughlin said: 鈥淚 believe the improvements will be very good for Birmingham. It will almost be a destination in its own right.
鈥淭here will also be improvements in capacity so that more people can use the station.
鈥淎 key part of this government鈥檚 long-term economic plan is investing in world class infrastructure. That is why we are putting record amounts of government funding into our railways over the next five years.鈥
He added that the transformation is all the more remarkable because the station has remained open throughout.
Mr McLoughlin also highlighted a 拢16 billion investment in HS2 over the next five years. Asked about why the project will take until 2026 to be completed, Mr McLoughlin said he is being lobbied from both sides 鈥 those who want it sooner and those who want it stopped.
鈥淲e have got to get it right, plan it carefully and look at the environmental considerations. It opens in Birmingham in 12 years鈥 time and that is not a huge amount of time for a project on that scale.鈥
