www.guardian.co.uk A Peruvian mayor has built a bridge leading to Machu Picchu, Peru's Inca citadel, despite warnings it will wreck the archaeological gem and open a route for drug smugglers. The 80-metre (260ft) long bridge over the Vilcanota river is due to open this week in defiance of a court order and protests from the government, which fears hordes of backpackers will swamp the site.

The UN conservation agency Unesco is due in February to inspect the mountaintop ruins, a world heritage site deep in the Andean jungle, amid concern that there are already too many visitors. But Fedia Castro, mayor of Convenciأ™إ½n province, said the bridge would end her community's isolation and give tourists a cheaper option than a train which, until now, had a monopoly on transport through the Sacred Valley. "It's almost ready, so they can't stop it," she said.

Locals have welcomed the bridge for opening their remote province to commerce and tourism. Instead of a treacherous 15-hour drive over mountain passes farmers can truck coffee and fruit to Cusco in just three hours.

The bridge, 12 miles from Machu Picchu at the town of Santa Theresa, replaces one washed away in a 1998 flood but which the government refused to rebuild. "We begged and shouted but they ignored us," said Ms Castro. The municipal and provincial authorities of Convenciأ™إ½n started building in January, using أ‚آ£570,000 of public funds. The final touches are being put in place.

The National Institute of Natural Resources filed a criminal complaint against Ms Castro last month after she ignored a court injunction demanding a halt to construction. Deputy tourism minister Alfonso Salcedo called the mayor reckless: "This we will not allow."

Officials also expressed alarm that Convenciأ™إ½n, which is under a state of emergency because of its coca production, could smuggle cocaine in the fruit and coffee trucks crossing the bridge. Peru is the world's second largest cocaine producer after Colombia.

The tourism ministry did not reply to queries last week about what, if anything, would be done to stop the bridge.

Since Peru's guerrilla war ended in the 1990s the number of visitors to Machu Picchu, 310 miles south of the capital, Lima, has soared to more than 4,000 tramping around the stone citadel daily.

Conservationists warned that the ruins were under stress and that wildlife along the Inca trail was disappearing, prompting the government to limit the number of visitors to 2,500 daily. Unesco is reportedly considering naming it an endangered heritage site.

Ms Castro said other Inca sites nearby could draw many of the tourists and relieve pressure on Machu Picchu, a secret city missed by the conquistadors and unknown to the outside world until an explorer stumbled across it in 1911.

Conservation concern, she said, was a red herring to protect the monopoly of PeruRail, part of Orient Express Hotels, which has operated the line since 1999. Every day hundreds of foreigners pay from أ‚آ£33 to أ‚آ£230, depending on how much luxury they want, for a return trip. With the bridge backpackers can take a أ‚آ£2.30 bus ride to the foot of the site.

The mayor alleged, but offered no proof, that three executives offered her a أ‚آ£255,000 bribe in 2003 to forget the bridge. A PeruRail spokesman, Gonzolo Rojas, rejected the claim.

Ms Castro lost her post in elections last month and is due to step down next week. She has disputed the election result. The new mayor has supported the bridge.