LONDON (Reuters) - Housebuilder Bovis Homes <BVS.L> on Tuesday warned on its first-half results and said the outlook for the rest of the year was difficult to predict, citing a sharp deterioration in the housing market.

Bovis shares fell 5 percent to 447-1/2 pence by 8:03 a.m..

In a statement ahead of its annual general meeting later on Tuesday, Bovis said the group's results for the first half of the year ended June 30 will be significantly lower than it had previously anticipated.

Bovis said reservations of new homes since it released full-year results on March 10 have been disappointing and reservations achieved so far in 2008 are down 30 percent on the year at 1,382 homes.

Bovis said a drop in the number of mortgages available and increases in mortgage rates and fees were deterring homebuyers, echoing comments late last month from Persimmon (LSE: PSN.L - news) <PSN.L>, the country's biggest housebuilder by market value, which said the market had deteriorated rapidly.

Last week, data from mortgage lender HBOS <HBOS.L> showed the housing market downturn was gathering pace with prices in April 3.7 percent lower than a year earlier.

Bovis said its sales prices have been, and will be, adjusted to reflect local market conditions.

(Reporting by Erica Billingham; Editing by Louise Ireland)