CALGARY — Aboriginal leaders in Alberta are supporting a business-led push for a moratorium on new oilsands development.

Chiefs from Treaties 6, 7 and 8 met last week and unanimously agreed that the Alberta government shouldn't let any new oilsands projects go ahead until First Nations have approved watershed and resource development plans.

Chief Allan Adam of the Fort Chipewyan First Nation, which is located in the oilsands region of northern Alberta, says thresholds have to be put in place that will protect the ecosystem and human health.

The chiefs' resolution states that the cumulative impacts of oilsands development "have all but destroyed the traditional livelihood of First Nations" in the area.

The move by the chiefs comes as major oil producers led by Petro-Canada, Suncor, Husky Energy, Shell Canada and Imperial Oil have for the first time called on Alberta to slow oilsands development.

The group, which also includes Devon Canada and ConocoPhillips Canada, has sent a letter to the Alberta government calling for the province to suspend land lease sales until at least 2011 in three areas around Fort McMurray.