The number of hotels under construction in L.A. County jumped in the first half of 2005, according to a new survey scheduled for release Wednesday.

While no new hotels opened in the county during the first half, L.A. County has eleven hotels under construction, for a total of 874 planned rooms a 68 percent increase from the year-ago period, according to the Mid-Year 2005 California New Hotel Development Survey by the Costa Mesa-based Atlas Hospitality Group. In the first half of 2004, four hotels opened in L.A. County for a total of 334 rooms.

Most of the openings in Southern California during the first half took place in San Diego County, where three new hotels opened with 817 rooms. San Diego County accounted for 40 percent of all new rooms opened statewide, but was up only 3.4 percent from the first half of 2004.

The busiest county for construction was Ventura, where 1,000 rooms were under construction during the first half, a 19 percent increase over last year.

Orange County had no new hotels open in the first half, compared to four hotels with 462 rooms in the first half of last year. But there are seven hotels under construction for 868 rooms, an increase of 125 percent over last year.

The Atlas report said the 15 percent overall increase in hotel rooms under construction shows “the continued strength of the California hotel market.”