Current plans from architect AHMM include a swimming pool and a running track on the roof and space for as many as 5,000 workers.
BAM Construction was due to start on site early next year but that will now be pushed back with the completion date delayed from 2016 to 2017 at least.
Sources close to the company told The Telegraph that plans will be resubmitted for new permissions to be granted but Google is unlikely to hire new architects.
A source close to the project said: “There was nothing wrong with the old designs – it would have been a great building – but we just decided to be even more ambitious.
“We are still completely committed to the project, which is good for Google and good for the UK too.”
Joe Borrett, Head of Real Estate and Construction at Google, said: “We have a great plan for the new building at Kings Cross, but we want to challenge ourselves to do something even better for Google, Kings Cross and for the local community.”