Funding for efforts to prevent the deadly mosquito-borne disease increased sharply between 2004 and 2009, part of an ongoing drive that has saved more than a million lives in the past decade, but has since levelled off, the UN's health body said.

"Millions of people living in highly endemic areas continue to lack access to effective malaria prevention, diagnostic testing and treatment," it said in a statement.

In its annual World Malaria Report, the WHO pointed out that last year, only $2.3 billion (1.75 billion euros) went towards fighting malaria globally -- less than half the estimated $5.1 billion needed.