The manifesto - ‘Taking the lead in global health' - argues that technology should be better used to tackle global health issues such as Aids, in terms of the delivery of treatment and education of the public.
The campaigning team at London agency Colman Getty PR, best known as a literary specialist, will target senior ministers across the main political parties, in the UK and overseas.
Behbehani's ultimate goal is to see the recommendations of the manifesto adopted by governments across the world.
The list of 13 candidates for the WHO director-general post was announced last week. The incumbent, Lee Jong-wook, died in May.
Colman Getty is initially retained for three months, until the winner is confirmed on 9 November.
Colman Getty is also seeking media attention and celebrity backing for the manifesto, targeting pop-stars such as U2's Bono and Coldplay's Chris Martin. International media and the medical press will be targeted.
The manifesto was published on 6 September, the day on which the WHO leadership nominations were announced.
Behbehani joined the WHO in January 1991. In 2003 he was made assistant director-general for external relations and governing bodies. He is also a WHO envoy.