At least three bidders including Italy's Snam and Australia's Macquarie are expected to place binding bids later this week for a 49% stake in pipeline company Gas Connect Austria, sources close to the matter said.

Gas grid company Snam is bidding in a consortium with Germany's Allianz, while Macquarie and Czech energy group EPH are expected to bid on their own, the sources said on July 26.

Final bids, expected to be in the region of 500 million euros (US$549 million) to 600 million euros, are due by July 29, a banker involved in the process said.

Two other sources said bids were expected before the end of July. Snam, Macquarie, Allianz and EPH declined to comment.

Austrian energy group OMV, which is 31.5% owned by the state, is selling a 49% stake in Gas Connect Austria to raise cash to fund investments as oil prices fall.

A spokesman for OMV declined to comment on the specifics of the bid process, saying only: "We want a signature by the end of the year."

With ultralow interest rates, infrastructure investments generating steady regulated returns are attracting increasing interest from financial players looking for safe yields.

Gas pipelines are also drawing interest from industrial players as Europe seeks to integrate its patchwork of gas grids.

Snam, Europe's biggest gas pipeline operator, is looking to play a leading role in the consolidation process designed to boost security of supply.

The company, which has a strategic alliance with Belgium's Fluxys, already controls French grid TIGF and Austrian pipeline TAG and recently bought a 20% stake in the Trans Adriatic Pipeline that will bring Azeri gas into Europe. (US$1 = 0.9106 euros)