The G8 summit has agreed to provide a further $5bn (£3.3bn) over five years towards improving the health of mothers and young children in the developing world.
Canadian Prime Minister Stephen Harper made the announcement at the summit in Toronto.
The funds are intended to help tackle one of the international targets known as the UN Millennium Development Goals.
But anti-poverty groups say the pledge does not meet the scale of the problem.
Together with other donations, including one from the Gates Foundation, the full pledge will amount to $7.3bn.
One of the Millennium Development Goals is to reduce by three-quarters the death rate among mothers and young children.
Mr Harper said he would like to achieve even more.
"We are committed to moving the world towards the day when women in developing countries will not die or suffer disabilities from pregnancy or childbirth," he told reporters.
However development lobby groups say they are disappointed by the $5bn pledge.
One said the initiative failed to meet the needs of many mothers and children in the poorest parts of the world.
Campaigners have also heavily criticised the G8 for falling short on a promise made at a previous summit to increase total development aid.