The creation of a "Dutch-style" segregated cycle lane in Bristol has been delayed until the spring.
The £380,000-lane, which will run along the River Avon at Clarence Road in Bedminster, had been due to open in the summer.
But the city council said it was working to stabilise the river wall and could not complete the cycleway until that work ends.
A spokesman for Bristol Cycling Campaign said it was disappointing.
The scheme, announced in February, involves narrowing the road, removing parking bays and constructing a separate 10ft (3m) cycleway and footpath.
Bristol mayor George Ferguson, an independent, said the scheme was modelled on similar cycleways from the Netherlands and Denmark.
The 2,300ft (700m) cycleway will be segregated from cars using small bollards, and from pedestrians by the existing kerb.
A council spokeswoman said it needed to permanently stabilise the river wall after noticing sudden movement under the footway following a number of high tides.
She said: "Council engineers have been closely monitoring the wall on a weekly basis since January and there had been no measureable movement until early August this year when, after another high tide, the wall moved forward in the direction of the river by around 145mm."
As a temporary measure, 53 one-tonne bags filled with stones have been placed in the river in front of the wall to try to prevent further movement.
The spokeswoman said work to finalise a permanent stabilisation scheme was continuing and she could not say how long it would last.
"We estimate the river wall project will be completed by early January 2015," she said.
"The finishing touches to the cycling scheme cannot be made until the stabilisation work is complete. The cycleway is expected to be open by the spring 2015."
Martin McDonnell, from Bristol Cycling Campaign, said: "It's disappointing because it's a trial where they're trying out something new.
"Things need to get into operation as soon as possible so we can get feedback on how successful it is."