The zig-zag path at Highcliffe Castle is to remain closed until 2018 because it needs a full rebuild.
The path was closed in March by Christchurch Council because of safety concerns.
Surveys which had been ongoing for more than a year, showed the retaining timber support could collapse at any time.
Now the council has set aside funds of £350,000 for the project and was also recently awarded around £280,000 towards the rebuild as part of the Dorset Coastal Community Bid.
Until the work is tendered the actual cost will not be known.
Specialist design work for the rebuild, which must have disabled access, is ongoing.
Because of the value of the works a full tendering process must take place once the final design is approved and it is likely that building works will commence in the autumn.
Depending on the weather it is likely that building work will take up to six months meaning the zig-zag path could reopen in time for Easter 2018.
Matti Raudsepp, Strategic Director, Christchurch and East Dorset Councils, said: “We had hoped to be able to reopen the zig-zag with a temporary solution for the summer season.
"However, recent surveys have shown that the cliff is no longer secure enough to enable a temporary solution to work successfully.
“We understand the closure has impacted on local residents and visitors but the safety of the public has to be our priority.
"The recent period of dry weather has further exacerbated issues in the area, and recent cliff falls locally demonstrate why it is essential we do not reopen the zig-zag path until we are confident that it is safe.
"We would like to thank people for their patience while the path remains closed.”
The council is looking at ways to better secure the closure of the footpath down to the beach until it is once again safe to use to ensure people to not try to use the zig-zag while it is closed.
It is also looking at options to improve the signage for the public to alternative routes and to provide information about the closure at the start of other routes which end at the popular castle site.