SNC-Lavalin has put up a "For Sale" sign on AltaLink, which owns more than half of Alberta's electricity transmission grid and is a wholly owned subsidiary of the Montreal-based company.

The company provided few specific details of its plan in Monday's announcement, which is part of a broader strategy of reducing its investments in infrastructure assets.

It says all options for AltaLink will be considered, including a private sale, strategic alternatives or turning to the public market.

AltaLink operates about 12,000 kilometres of transmission lines and 280 substations in the province, serving about 85 per cent of the population.

It also received regulatory approval in December for a $1.5-billion transmission line extension to run 350 kilometres from Genessee, west of Edmonton, southward to Langdon, east of Calgary.

"Through the company's expertise in transmission and distribution project development, AltaLink has become a unique asset that has achieved the strategic objectives necessary to offer value to new investors, whether public shareholders or financial or strategic partners," SNC president and CEO Robert Card said.

He also said that the AltaLink's ongoing expansion plan will continue.

AltaLink is part of SNC-Lavalin's concessions portfolio, which also includes the Highway 407 toll road near Toronto, a Montreal hospital and the Montreal symphony hall.

Earlier this year, the company signed a deal to sell 66 per cent of its minority interest in Astoria Project Partners II LLC, which owns and operates the gas-fired Astoria II power plant in New York City.