BIDS TO build the £180M privately financed second Tyne tunnel are expected to be invited this autumn after the project won formal planning approval last week.
Transport Secretary Alistair Darling's decision to give the project the green light remains open to legal challenge until the beginning of October.
But Tyne & Wear Passenger Transport Authority expects to invite tenders for the design build finance and operate project soon after that date.
Four potential bidders have already expressed interest in the project. Three are headed respectively by Balfour Beatty, Laing O'Rourke, and Bouygues.
The fourth comprises Mowlem, Nuttall and Vinci.
Construction of the 2.6km two lane crossing is not expected to start until early 2007. The central 360m section will be an immersed tube, linked to cut and cover approach tunnels on each bank.
A dry dock for the construction of the immersed tube sections will probably be built nearby at Howdon Basin.
The tunnel cross section currently features a single cell housing road traffic and an escape corridor. It is not yet known if sprinklers will be fitted to control vehicle fires.
When the tunnel opens in 2010 it will relieve pressure on the existing two lane Tyne Tunnel which takes the busy A19 under the river east of Newcastle-upon-Tyne.
Currently 34,000 vehicles use the tunnel every day, well above its 25,000 vehicles a day design capacity.