STOCKHOLM, June 19 (Reuters) - Swedish commercial property company Fastpartner has sought to reassure investors of its financial stability after Moody's had cut its credit rating to junk status.

Fastpartner has enough cash to handle debt maturities for more than 30 months, it said after Moody's had cut its credit rating late on Friday.

High debt, rising interest rates and a wilting economy has proved a toxic cocktail for Sweden's commercial property companies, with some cut to junk by ratings agencies. Commercial landlord SBB is at the centre of the spiral.

Concern over the sector is weighing on the nation's currency while investors are wondering if Sweden will be the first domino to fall among beleaguered property sectors across Europe.

"More companies with downgraded credit ratings increase the perception of Swedish real estate companies as highly leveraged," said Carlsquare analyst Bertil Nilsson.

Moody's had said late on Friday that it would lower its rating on Fastpartner, which owns mainly commercial property, to Ba1 from investment grade Baa3.

Shares in the company were down 9.3% at 40.65 Swedish crowns by 0836 GMT on Monday. Fastpartner said in a separate statement that it had recently strengthened its financial stability by extending the terms of existing bank loans and rapid credit facility agreements.

"The implication of these measures is that we have liquidity to handle all debt maturities for a period exceeding 30 months," said CEO and majority owner Sven-Olof Johansson.

"In light of this and the company's relatively low share of outstanding bond loans, the lowered credit rating has marginal significance for the company's day-to-day operations."

Johansson is the fourth-largest shareholder in crisis-hit SBB and also sits on its board.

There is a large amount of cross-ownership among various real estate companies and private individuals, which has been raised as a concern by Swedish authorities.

Sweden and Germany are among the worst affected by a widening property slump on the continent, according to European Union data provider Eurostat. (Reporting by Anna Ringstrom and Marie Mannes in Stockholm Additional reporting by Jesus Calero in Gdansk Editing by Louise Heavens and David Goodman )