The estimated number of adolescents dying of Aids in the Asia Pacific region has more than doubled since 2005, experts said, warning of a "hidden epidemic".

Unicef urged Asian countries to improve teenagers' access to testing, saying many young people do not know their HIV status because of parental consent requirements for tests.

The Asia Pacific region has made enormous strides against HIV/Aids in the adult population, with a 31 percent drop in new HIV infections between 2000 and 2014, and 28 percent decline in Aids-related deaths between 2005 and 2014.

However, one in seven new infections in the region last year was among 15 to 19-year-olds, and the estimated number of Aids-related deaths for adolescents aged 10 to 19 has shot up 110 per cent to 6,600 in 2014, from 3,100 in 2005, a U.N. report said.

At-risk adolescent groups include gay and transgender youth, injecting drug users, and people who buy and sell sex.

"This is the first, definitive report on adolescents - teenagers between 10 and 19," said Wing-Sie Cheng, Unicef regional adviser on HIV and Aids.