Engineering group Downer EDI says it's won New Zealand contracts worth more than $400 million.

The projects include a construction contract secured by its joint venture with Soltanche Bachy to build an underground rail link in Auckland.

It did not detail the value of individual awards, but said other wins included a Coastal Otago highway maintenance contract, an alliance to manage the Milford road network and three projects in Christchurch for the earthquake recovery authority.

Downer, whose main mining division has suffered a sharp revenue drop in the past two years, has been looking to build capability in light rail design and construction and utilities services.