Increased tourism on the world's iciest continent and its impact on the environment were set to top discussion at an annual Antarctic Treaty meeting that began Monday in Brasilia.

"Some countries view the question with concern and believe that there is too much tourism in the region," said Manoel Silva Rodrigues, secretary of Brazil's commission on maritime resources.

A lack of preservation regulations has some countries expressing worry at the 37th annual gathering.

Around 32,000 tourists visit Antarctica each year, said the head of the Chilean delegation, Francisco Berguno.

That's well above the fewer than 5,000 tourists who journeyed to the continent annually in the 1990s. Cruise ships and airplanes have vastly multiplied the number of visitors in recent years.

The Antarctic Treaty sets out terms for the continent to remain a non-military zone and free for scientific research, to protect its environment, and to affirm Antarctica's territorial sovereignty.

Meetings for the treaty, which came into force in 1961, will continue through May 7. Other topics for discussion include the progress of biological research and conservation of fauna and flora, besides cooperation between the member states.