The Mott MacDonald designed project will raise the existing flood defences along both banks of the river Ness by constructing short walls and embankments.
Inverness has suffered serious flooding in the past
The Highland Council hopes the project will protect around 800 homes and 200 businesses in the city centre.
Irish contractor Coffey Construction started work last month diverting utilities ahead of the £13m phase 1 programme along the central city area of the river.
Firms were today invited to prequalify for the city work programme, which will involve constructing a reinforced concrete flood wall on top of the river bank, clad in stone.
Piled foundations also need to be installed to control seepage over the 18-month contract.
Bids for Phase 2 improvements downstream of Friars Bridge will be invited next year.
Further information can be obtained from:
Highland Council, Strategic Procurement Division, Dorothy Low, The Town House, High Street Inverness IV1 1JJ. Tel: +44 1463703885