The world's biggest hotelier, InterContinental Hotels, expects its London rooms to be about 90 percent full for the Olympic Games as the world's sports fans flock to Britain for the two-week extravaganza.

Chris Hale, the group's head of London 2012, said its key revenue measure could also be boosted, and countered criticism that rooms during the Games are too expensive by pointing to "lots" of availability at less than 100 pounds ($160) a night.

"We would expect 80-85 percent occupancy in a typical London summer, but this summer we would expect the figure to be around 85 to 90 percent," Hale told Reuters in an interview on Tuesday, ahead of the London Olympics which start on July 27.

The owner of the Holiday Inn and Crowne Plaza brands as well as InterContinental has 51 hotels within London's orbital M25 motorway and at its airports.

Hale expects the group's 10,000 hotel rooms in the city to be largely full despite Games organizers releasing thousands of pre-booked hotel rooms back on the open market this year.

Organizers booked a third of London's hotel rooms, or about 40,000, for Games officials, media and sponsors at a few percent below current rates, but in January released 20 percent of these back on the market.

Despite this, Hale expects revenue per available room (RevPAR), a key industry measure, to be between flat and 2 percent higher at his London hotels over the summer.

With fewer rooms on the open market, criticism has mounted about hoteliers pushing up prices. Last week hotel wholesaler JacTravel forecast bookings will be down by a third compared with last year, with travelers put off by high prices.

"We still have lots rooms available at good rates, with a Holiday Inn room within one hour travel time by public transport to the Games at less than 100 pounds a night," Hale said.

The hotelier owns one of its 51 London hotels - the Park Lane InterContinental - with the others being franchised or managed, so it has no direct control over their room rates.

Hale insisted room rates would be "realistic" and the group would offer its advice and guidance to the owners of hotels if it believed room rates were too high.

He added its 447-room Park Lane InterContinental and the 350 combined rooms at its Holiday Inn and long-stay Staybridge Suites hotel at the Olympic site have been fully booked by the organisers, while the group is also managing the 17,000-room athletics village during the Games.

($1 = 0.6447 British pounds)

(Reporting by David Jones; Editing by David Hulmes)