QUEBEC CITY, aug 19 (reuters) - quebec city, a united nations world heritage site because of it exquisite 17th century buildings, fortified walls and cobbled streets, stands accused of constructing a modern eyesore to draw in more tourists.

that's the view of residents who live in the city's old town, who are up in arms over the squat blue cruise ship terminal erected on the banks of the st lawrence river just outside the city's historic walls.

native quebecers say the new terminal sets up a clash of cultures between centuries old architecture and modernist trends, as well as a clash of interests between local residents and a huge tourist industry.

"it's an unspeakable, monstrous structure," resident marie-paule tremblay wrote in a letter to le soleil newspaper.

quebec city's harbour authority, which is distinct from the city government, is unashamed of what it has wrought.

"we are very proud of the terminal, it's one of the nicest in canada," ross gaudreault, general manager of the port of quebec city, told reuters.

"every day when i walk on the banks (of the river), people tell me that the terminal looks good and that they are proud of it," he said.

the steel and metal structure was built to handle the record 80 cruise ships and 70,000 passengers expected to dock at quebec this summer. that's up from the 48,000 passengers who arrived last year, but only a fraction of the estimated six million visitors the city gets each year.

'architectural horror' the passengers are expected to bring c$10 million ($6.3 million) in economic benefits to the french-speaking city. but tourist dollars can't bribe many old towners into liking what they consider to be a desecration of their urban jewel. "it's an architectural horror," local resident jean-pierre ajmo told reuters. "they want to promote the tourist industry, but they don't care about the heritage, and destroy an extraordinary panorama."

quebec city was founded on the st lawrence in 1608 by french explorer samuel de champlain. the port allowed ocean-going ships to travel deep into the continent and the city grew around it, and on the cliffs above, to become the commercial and administrative centre of new france.

the terminal complex, built to cash-in on the growing popularity of cruises, opened in june near the city's place royale, a public square in the old port.

built at a cost of c$23 million ($13 million), the terminal is located in the old port just under the cliff where the renowned chateau frontenac hotel stands. it is connected to a 150-foot (45-metre) footbridge that leads passengers to the customs and immigration office. the footbridge stands on a large blue container-like platform erected on tall wheels. stairways are attached to it.

a group of residents -- who successfully blocked the construction of an imax movie theatre in their neighbourhood in the 1990s -- had been fighting the cruise terminal for years.

this time, they didn't win.

they called upon unesco, but the united nations body said there was little it could do as the municipal, provincial and federal governments had approved the project.

"it was getting too political and we didn't want to get involved in that," said mathias bizimana, programme officer for culture and world heritage at the canadian commission for unesco.

"the authorities saw the economic interests and moved ahead with the project," he said, adding that the terminal was outside the heritage area.

the city would rather have seen it built at a cove 1.3 miles (two km) away from the centre.

"it was the port's decision," said quebec deputy mayor jacques joli-coeur who conceded that he was not comfortable with the design of the terminal.

"i have to say that the colour and the rustic aspect of the footbridge is striking...it clashes," he said. ($1=$1.58 canadian)