* Bid subject to review; decision possible by next month
* Project initially attracted 7 prospective bidders
* Sole bidder means review likely to be quick (Adds comments from bid panel head, context)
MANILA, May 28 (Reuters) - A consortium led by Philippine conglomerate Ayala Corp has submitted the lone bid to undertake a 64.9 billion peso ($1.5 billion) project to renovate and extend Manila's oldest elevated railway.
The bid from Ayala, Metro Pacific Investments Corp and Macquarie Group Ltd will be reviewed to ensure it meets bidding rules, and a decision could be announced by next month, Transportation Undersecretary Jose Perpetuo Lotilla told reporters after the auction on Wednesday.
Winning the auction would kick off the biggest infrastructure project so far under a Public-Private Partnership (PPP) programme started in 2010 by a government aiming to boost economic growth with investment in roads, railways and airports.
The winning bidder will renovate Manila's 30-year-old LRT Line 1, extend it 11.7 km south to Cavite province, and operate the line for 35 years.
The project initially attracted interest from seven parties including conglomerates San Miguel Corp and DMCI Holdings Inc, as well as Megawide Construction Corp
The other prospective bidders were Spain's Globalvia, France's Ecorail Transport Services and a consortium comprising Malaysia's MTD Capital Bhd and South Korea's Samsung C&T Corp.
Only San Miguel and DMCI gave notice of their intention not to bid, said Lotilla, who heads the bids and awards committee. Others asked for more time or requested certain conditions, he said.
"In accordance with the law and rules, the bidding may proceed even if only one bid has been submitted," said Lotilla. "This project has already been delayed once, so the government believes that it would be difficult to justify further delay."
The project was first auctioned last year and received a single bid from the Light Rail Manila Consortium, led by Metro Pacific Investments Corp. The bid was rejected, however, as it did not comply with bidding rules.
At the latest auction, as the bid from the Ayala-led consortium is the only bid, the review process should be relatively quick, said Cosette Canilao, executive director of the PPP Center. (Reporting by Siegfrid Alegado; Editing by Christopher Cushing)