The disease, which increases the chances of gay men catching HIV, is usually treated with a course of antibiotics but doctors say that they are seeing increasing resistance to drugs in the eastern hemisphere.
According to WHO, cheaper, first-line antibiotics are losing their effectiveness and it will be a "matter of time" before gonorrhoea develops resistance to third-generation cephalosporin, which is usually the last drug used to treat infections.
Australia, Hong Kong and Japan have reported treatment failures with oral cephalosporin, the agency said.
Studies show that the overuse of antibiotics can render bacteria immune to them.
"We are dealing with a serious issue with the implication that gonorrhoea may become untreatable," said Dr Shin Young-soo, WHO regional director for the Western Pacific.
"This will have a major impact on our efforts to control the disease and will result in an increase in serious health-related complications."
If left untreated, gonorrhoea can result in infertility, pelvic inflammatory disease, ectopic pregnancy, infections in newborn children, urethral strictures and scrotal swelling.
It also increases the likelihood of acquiring and transmitting HIV infection, which disproportionately affects gay men.
Matthew Hodson, head of programmes at GMFA, the gay men’s health charity, said: “Hearing this report is a major concern. Not only can gonorrhoea have major health consequences, such as inflammation of the joints and septicaemia, but also it can considerably increase the likelihood of HIV being transmitted.
"HIV positive men with gonorrhoea will be more infectious. HIV negative men with gonorrhoea will be more vulnerable to HIV infection."