* UBS launches Swiss Real Estate Bubble Index
* Index value at 0.63 in Q1 2011
* Value above 1 means market seen as risky
ZURICH, May 30 (Reuters) - Switzerland's residential real estate market is in a boom phase and not a bubble, the UBS Swiss Real Estate Bubble Index showed on Monday.
In the first quarter of 2011, the index, launched by UBS Wealth Management Research Switzerland, was at 0.63. The market is considered risky when the index goes above a value of 1. The index reached its peak in the early 1990s at a level of 2.5 at the height of the last Swiss real estate bubble, UBS said.
UBS said the most risky regions were Zurich, Geneva and Lausanne.
Swiss housing prices have more than doubled within a decade in many areas.
"Real estate bubbles pose a substantial risk for national economies, as countries like the United States, Spain, Ireland and others have recently experienced. Strong increases in home prices in Switzerland are giving cause for concern," UBS said.
"Is a real estate bubble developing in Switzerland, too? There is no simple answer to this question," UBS said.
The Swiss National Bank has said it is keeping a close eye on the housing and mortgage market and has warned that low interest rates might tempt banks to loosen their lending standards and trigger a house price bubble. (Reporting by Katie Reid; Editing by Will Waterman)