Investment is estimated at €575 million, Madrid-based Cintra said. The 50-kilometre M-3 toll road will link Clonee and the north of Kells, northwest of Dublin.
The Spanish company owns 95% of the venture for the new contract and Siac Construction the rest, Cintra said. Siac may increase its stake to 25%, Cintra said.
The group was named preferred bidder in September and the contract lasts 45 years.