A shortage of hotel rooms has led Rio authorities to invest millions of dollars to convert raunchy motels to accommodate the legions of tourists expected for the 2014 World Cup and the 2016 summer Olympics.

Shalimar, located in the upscale beach district of Leblon, is one of 60 such "sex" motels undergoing a facelift.

Already 30 of its 62 rooms have been remodeled and given a minimalist look.

Out with the red carpets, the mirrors, the heart-shaped water bed and the chains on the walls.

Outside one debris-filled room, a large Venus sculpture, dirty and broken, lies forlornly, destined for the garbage dump.

According to Rio Negocios, the city's investment promotion board, more than $100 million has been earmarked to convert 3,500 of Rio's 6,500 motel rooms, with local authorities providing tax incentives.

"We have a (hotel room) supply problem but we are working on it," Rio Mayor Eduardo Paes told AFP.

"We will have 16,000 additional beds. We will also use motels. This is something new. That could be an adventure for a couple, an opportunity for new experiences," he added with a giggle.

This world-famous city of six million people today has 32,436 rooms: 20,414 in hotels and 12,022 spread out in motels, apartment hotels, inns and hostels.

The goal is to bring the total up 47 percent to 47,788 by 2015.

"Motels will be an option for those who come to Rio, along with budget hotels in upscale areas of the city," said Alfredo Lopes, president of the Brazilian Association of Hotel industry (ABIH-RJ).

Traditionally, local sex motels are full during the high season -- Carnival or the New Year -- or during high-profile events such as the 1992 Earth Summit and the visit by the late Pope John Paul II in 1997.

"Foreign dignitaries would troop to their motels after their activities and ran into regular clients. It was a strange atmosphere," recalled Sports Minister Aldo Rebelo.

And he welcomed as a "good idea" moves to convert the motels into "real hotels".

The conversion process began two years ago but accelerated last June with the holding of the UN Rio+20 environment summit.

There is also a growing demand for affordable, quality accommodation for staff of the many oil companies that have recently set up operations in the Rio area.

And motel employees are getting special training and language courses to deal with this new clientele.

The boom in sex motels reached its peak in the 1970s and 1980s.

"Every teenager wanted to reach the age of 18 to be able to visit a motel," recalled Antonio Cerqueira, the Shalimar owner and vice-president of ABIH-RJ.

But the boom ended due to the economic crisis in the late 1990s, the proliferation of AIDS cases and a cultural change in families.

"Before you could not imagine bringing your girlfriend in your parents' home, but in the past few years it has become normal," Lopes said.

In recent years, middle-aged people have replaced the young in sex motels, "thanks to wonder pills (viagra)", according to Cerqueira.

Meanwhile at the Shalimar, one room dubbed "the Medieval" has been spared.

Adorned with chains and granite ornaments simulating a castle tower, it is one of most sought-after by the traditional clientele.

"If we tamper with it, they (the clients) will kill us," said a Shalimar employee, flashing a wide grin.