The redesign of Euston station in preparation for the launch of the new high-speed rail line is likely to take up to seven years longer than originally planned and won’t be completed before 2033.
HS2 Ltd, the company responsible for the network, unveiled a redesign of its initial proposals which it claimed would increase efficiency and reduce disruption to local residents.
However, in response Camden Council warned that the project would bring "more than a decade of blight" to the area.
The building work, which is set to begin in 2017, was due to be completed by 2026. HS2 Ltd now plans to continue the work until 2033.
It wants to build six platforms and a concourse to the west of the existing station by 2026 to support the first phase of HS2 between London and the Midlands.
In a change from proposals initially submitted two years ago, HS2 Ltd is planning to delay construction of five further high-speed platforms within the existing station. They would be ready for phase two of HS2 which will run from the capital to Leeds and Manchester in 2033.
"It is more construction over a longer period but it's less intense,” said Rupert Walker, Euston development director of HS2 Ltd. "It will be easier for us to manage."
He said that under the original plan the five new platforms within the existing station would have sat unused for up to seven years until phase two was ready.
"That is not a particularly efficient use of the new infrastructure and there was a price to be paid to do that," Walker explained. "Building all 11 platforms in one go would have taken five platforms off the existing use of the station.
"That would have meant we would have had to reduce the number of trains coming in and out of Euston every day."
The new plans will be submitted to Parliament next week.
Sarah Hayward, leader of Camden Council, warned that the proposal would let down the capital as a whole unless there was "close collaboration"
between all important parties.
"HS2 will cause decades of blight in the Euston area - to property prices, to our small business' trade and to our residents' lives, which is why we remain ardently opposed to the scheme," she said.
"The success of the new King's Cross was built on close collaboration between key partners and viewing the area's needs as a whole.
"Euston is a different case, but we need bodies like HS2 Ltd, Network Rail and Transport for London to work together with us, residents and businesses to ensure the new Euston works for everyone."
HS2 Ltd said its proposal was a "flexible scheme" and insisted Network Rail, which owns the station, will announce its own plans in due course.