Poor access to health services and higher rates of infectious diseases, diabetes and heart disease may lead to the extinction of certain indigenous groups, policy analysts say.

Indigenous people make up about six percent of the world's population, in about 5,000 separate groupings, according to some estimates. However, studies reveal that life expectancy within these groups is considerably lower than in other populations, according to the online edition of New Scientist.

A group of international researchers is now calling for the global community to revise its health plans to better serve the needs of these people.

Research has revealed that in Western Australia, an aboriginal child is three times more likely to die in infancy than a non-aboriginal child.

Similarly in some areas of Latin America, oil exploration has threatened the existence of indigenous groups in forested areas.

These people could disappear forever because of the poor access to health services and higher rates of infectious diseases, diabetes and heart disease, compared with non-indigenous counterparts, they said.

In 2000 nearly 150 heads of state signed a historic document known as the Millennium Declaration, aimed at promoting health and boosting income for the poorest people across the globe.

This led to the UN's Millennium Development Goals (MDGs), a series of concrete targets to reach by 2015, such as halving the number of people that live on less than $1 a day.

But in this week's issue of "The Lancet", a range of experts argue that the implementation of these goals has been uneven and that poorer people in hard-to-reach regions of a country are less likely to benefit.

They believe that the goals should be revised to ensure that countries do not forget about minority population when implementing campaigns to improve health and income.

However defenders of the MDGs say that the targets are flexible and that nations are encouraged to decentralise the implementation of related programmes so that minorities in remote areas benefit from the plan.