LEIGHTON Holdings has secured $1.2 billion worth of contracts linked to the $34 billion Ichthys liquefied natural gas project in Darwin.

The first contract, worth $923 million, is to build infrastructure such as roads, foundations and trenches at Blaydin Point for Ichthys' onshore facilities.

Construction is due to start in May and be completed by July 2016, Leighton Contractors said on Friday.

It is the third project Leighton has won for the Ichthys onshore site.

Separately, the company said it had clinched a $280 million operations and maintenance contract for Blaydin Point's temporary facilities.

Leighton Contractors will operate and maintain services for all temporary site facilities, including power supply, water-treatment plants and pest control, for more than four years during the construction phase.

The temporary facilities will be built by Leighton Contractors' infrastructure division.

''We see the LNG and coal seam methane markets offering significant opportunities for the Leighton Group, which has developed a high degree of competency in delivering essential infrastructure for large resources projects,'' Leighton chief executive Hamish Tyrwhitt said.

The Ichthys gasfield is about 200 kilometres off the West Australian coast. It is expected to produce 8.4 million tonnes of LNG and 1.6 million tonnes of liquefied petroleum gas a year.

Leighton shares closed 5¢ higher at $17.89.

AAP