The planned Oostbrug, a cycling and walking bridge between the Eastern Docklands and Noord, is at least €169.5 million short of funding for its cheapest design.
It would run from the Azartplein to the Hamerkwartier, so people could cross the IJ without a ferry.
Costs have risen sharply
Early plans assumed about €325 million, but estimates have since come in at €650 million to €850 million.
The city has €522.5 million available, including €42 million reserved for future price rises.
Deeper foundations, protection against ship collisions, movable sections and dearer materials and labour all add to the bill.
In September it emerged that the city had higher estimates before the municipal elections but kept them from the council.
The 2034 opening is in doubt
Building was due to start around 2031, with an opening in 2034, but that timetable is now uncertain.
More clarity on the financial and technical options is expected in spring 2027, when residents can comment on cycle routes through the Eastern Docklands.
Alderman Elise Moeskops says the ferries cannot keep up with growth and calls the bridge the best and fastest option.
Until the bridge exists, check out our guide to Amsterdam’s ferries.