Spain's Habitat the latest victim of ailing sector

* Spanish property firm Habitat files for administration

* Has debts of 2.3 bln euros

* Colonial says its solvency may depend on asset disposal

* Analysts say may struggle to sell FCC, SFL stakes, Riofisa

(Adds Colonial statement, updates shares to close)

By Andres Gonzalez and Sarah Morris

MADRID (Reuters) - Unlisted Spanish real estate company Habitat filed for administration on Friday with debts of 2.3 billion euros ($3 billion), the second largest default in Spain after fellow property firm Martinsa Fadesa (MFAD.MC).

Spanish property firms have suffered falls of over 30 percent in house sales this year as the real estate sector seizes up in a global financial liquidity squeeze. Martinsa Fadesa filed for administration in July.

The move by Habitat, about 20 percent owned by building group Ferrovial FER.MC, came after indebted property firm Colonial (COL.MC) said it could be forced into administration if it fails to sell stakes in a number of companies.

Colonial later stressed it was not in insolvency proceedings and its situation had improved since signing an agreement with creditor banks. It made the comments as standard risk statements as enforced by the stock market regulator, Colonial said.

Habitat said property sales would continue as normal and it would work with administrators to reach a deal with creditors.

"Habitat is a viable project which is heavily affected by the current financial-property crisis, but which has high-value assets which support it and give it solidity," Habitat Chairman Bruno Figueras said in a statement.

Habitat said at the end of June it owed 232.3 million euros to La Caixa and 218 million to Caja Madrid, Spain's two largest savings banks, and 190 million to bank BBVA (BBVA.MC).

COLONIAL UNDER PRESSURE

Colonial, Habitat's larger listed rival, said it needed to complete a 1.41 billion euro convertible bond issue and sell subsidiary Riofisa, or a large part of it, together with stakes in builder FCC (FCC.MC) and French group SFL (FLYP.PA).

"If Colonial could not meet the sale obligations described, in the period agreed in the case of Riofisa, the company would not be able to meet its payments on the long-term restructured debt," said Colonial in the prospectus for its bond issue.

"All that could cause a substantial adverse effect on its business, its results and the financial state of Colonial or even, ultimately, insolvency and the entering into administration of the company."

The stake sales were agreed as part of Colonial's 6.5 billion euro five-year refinancing announced in September.

Colonial declined to reveal the deadline for selling Riofisa, saying it was confidential.

Many Spanish property firms are struggling to sell assets to pay down debt accumulated in Spain's decade-long housing boom.

Construction and real estate firms hold over a quarter of debt in Spain and represent over a quarter of all suspended debt payments, according to Bank of Spain and government data.

Analysts expressed scepticism about Colonial's chances of selling the assets in a market where there is little appetite for property assets and where financing is tight.

"Managing to sell stakes at acquisition prices is very challenging," said Bruno Silva, an analyst at BPI. A possible scenario is for Colonial's creditor banks to take the stakes, he said.

Colonial said on Wednesday it was still seeking buyers for the stakes but had given its creditor banks buy options which they could exercise between Dec. 11, 2008, and Jan. 10, 2009.

Habitat shareholder Ferrovial closed 6.1 percent lower on Friday at 19.64 euros, against a 0.7 percent fall in the DJ Stoxx construction and materials index .SXOP. Colonial closed 1 cent higher at 0.18 euros. (Additional reporting by Sonya Dowsett; Editing by David Holmes and Simon Jessop)