One of the key architects of a UN initiative to end world poverty has accused the Abbott government of shirking its responsibilities by slashing aid spending.

Jeffrey Sachs is the UN's special adviser on the millennium development goals (MDGs), which comprise eight targets that aim to significantly improve living standards for the world's poorest people by 2015.

One of the commitments rich nations made as part of the MDGs was to lift aid spending to a percentage of gross national income - a pledge postponed by Labor and abandoned altogether by the coalition.

The government also confirmed $7.6 billion worth of cuts to the aid program over five years, which is the biggest savings measure announced in the budget.

Professor Sachs said it was disappointing Australia had balanced its books off the back of the world's poor.

"I think these aid cuts really are completely unacceptable and outside of the spirit of the values of this country," the world-renowned economist and bestselling author told AAP in Canberra.

"It really cannot be the case that one of the world's richest countries said, 'Nah, we don't have to follow through on our promises or commitments'."

Foreign Minister Julie Bishop says many nations won't reach their MDGs by 2015, including in Papua New Guinea, where none will be achieved despite massive aid assistance from Australia.

She has argued that since the MDGs were forged in 2000, the focus has shifted to economic development, which has helped lift hundreds of millions of people out of poverty in the Asia-Pacific region.

The government will soon unveil a new strategy for the aid program, focusing on economic transformation and performance benchmarks to ensure goals are met and value for money is achieved.

Prof Sachs said there was ample evidence about the best ways to invest aid money, and it was the government's responsibility to find solutions instead of simply cutting back.

"I said to the government officials, if you don't know how to invest the money, here's my email address," he said.