Procurement will get underway at the end of this month after the Government cleared final funding for the huge Mersey Gateway river crossing.
The planned six lane toll bridge will span the Mersey between Runcorn and Widnes and will relieve the congested and aging Silver Jubilee Bridge.
As a condition of funding £30m in savings must be found, mainly expected from early design changes.
The council is also confident that it will achieve big savings from a competitively fought bidding race, like that achieved on the Forth Replacement Crossing.
Total construction cost, including land purchase and remediation, is expected to be £589m. Seventy percent will be funded by the private sector.
David Parr, chief executive of Halton Borough Council, said: “Today’s announcement means that we can now begin the procurement phase, which is all about selecting the best possible private sector partner to work with the council to design, build, finance and operate the scheme.
"We will also be consulting very soon on some of the details of the changes that will save around £30m on the cost of the project.”
The procurement process is planned to commence later in October, leading to construction work starting within two years. The bridge will take around three years to complete.
Steve Nicholson, Mersey Gateway project director, said: “We have been working very closely with Government over recent months to finalise the details of this agreement.
"This represents the best possible deal for the public purse and means that we can focus on delivering a project that will bring benefits to local people, commuters and businesses from across the region.”
The Department for Transport has agreed to stump up £470m for the project over its lifetime.
This is made up of £86m in direct capital grant and up to £14.55m per year in long term revenue support for 26.5 years after opening.