More than half of Denmark's police force will be deployed to ensure security at a major international climate conference in Copenhagen in December, police said Monday.

"This is the biggest operation we have ever taken part in," Peter Ibsen, who heads up the Danish police union, told AFP.

"We will need at least ... 6,000 men. That is more than half, since there are a total of around 10,970" police officers in Denmark.

The conference, aimed at reaching a new pact for curbing greenhouse gases beyond 2012 when provisions under the Kyoto Protocol expire, is expected to gather numerous heads of states and governments and thousands of lower-level officials in the Danish capital between December 7 and 18.