* First-quarter loss widens

* Warns of liquidity risks

* Shares rise in after-hours trade

NEW YORK, May 5 (Reuters) - Maguire Properties Inc (MPG.N: Quote, Profile, Research), one of the largest office landlords in Southern California said on Tuesday its first-quarter loss widened and added it may face liquidity risks if it cannot sell assets or raise more capital.

The company has $259 million of debt maturing in 2009, primarily from two construction loans, one maturing next month, the other in September. It is trying to sell the properties or extend the loans.

"If we are unable to sell these properties and cannot extend or refinance these loans, we could potentially default under the loans," Maguire said.

The Los Angeles based company has been struggling with its debt load since it bought a portfolio of properties in Orange County just at the height of the market in 2007. That was compounded by the collapse of several subprime mortgage brokers, some of whom were Maguire tenants.

At the end of the quarter, Maguire had interests in 34 million square feet, consisting of 35 office and retail properties, a 350 room hotel, parking lots and one project under development.

Maguire warned that it could not generate enough cash from operations, assets sales or more unsecured debt financings it "will have liquidity related problems and may be exposed to significant risks," the company said in a statement.