Updated

By Nicole Mordant

VANCOUVER (Reuters) - Vancouver showcased its nearly completed Winter Olympic venues on Tuesday as officials turned their attention to the thorny issue of how to maintain competition ice in this perennially wet and humid city.

With the start of the Games less than a month away, Olympic ice makers are just starting the painstaking process of creating ice surfaces of the required texture and thickness at the city's Olympic speed skating and curling rinks.

Through past experience, Olympic "ice meisters" have a better handle on how to deal with problems like heat from television lights.

But the Pacific Coast city's traditionally soggy climate presents new hurdles, said Neil Houston, ice maker at the Vancouver Olympic Center, the venue for the curling tournaments.

The rink is the biggest Olympic curling venue yet, with seating for some 5,600 people -- a possible threat to the perfect competition ice as the throngs of bodies warm up the building

If it's raining, the water brought in on peoples' clothes will evaporate inside the building, possibly causing the ice to frost over if the rink's surface gets damp.

"The major challenge is that we haven't had 6,000 people and pouring rain," Houston told more than 100 foreign and local reporters on a tour of the curling venue, set in a leafy Vancouver suburb.

Frost on the ice could slow down speed skaters, said Mark Messer, ice maker at the Richmond Olympic Oval, which will host all the speed skating events.

"It may affect the (skaters') times," said Messer, who was involved in ice making at three previous Winter Olympics.

Vancouver's competition venues will officially open on February 4 for athletes to begin training on them, while the Olympic events begin on Feb 12.

Vancouver and surrounding suburbs are home to the venues for skating, hockey, curling, freestyle skiing and snowboarding.

All venues are on schedule, with most in the final lap of being fitted out with items like extra bleachers and lighting, said Jan Damnavits, Vancouver venue director.

The mountain resort community of Whistler, about 125 km (78 miles) north of Vancouver, will hosts Alpine and Nordic skiing events, plus bobsleigh and luge. Organizers plan to give reporters a look at those venues on Wednesday.

(Additional reporting by Allan Dowd in Vancouver)