Christian Aid has added its voice to criticisms against the Government after aid was left out of the Queen's speech.
The development agency applauded the Government for committing to aid spending of 0.7% this year, but said the failure to enshrine this in law would affect the impact of aid within recipient communities.
Christian Aid's senior UK political adviser Sol Oyuela also urged the Government not to give in to pressure to spend aid money on military peacekeeping missions.
"Failing to enshrine in law the principle that 0.7 per cent of GNI should go on overseas aid is a broken promise," said Oyuela.
"Legislating to that effect was a manifesto pledge by all three major parties which now seems consigned to permanent postponement.
"But there are important reasons why legislation is needed. Academic analysis, shows that a key determinant of aid impact is predictable financing. Aid at present is notoriously unpredictable, with commitments made and not met, and frequent reversals over time rather than steady flows to individual countries. Legislation would have countered that."
It follows criticism from Tearfund chief executive Matthew Frost who said he was "bitterly disappointed" that the Government appeared to have broken its aid promise.
He said people had a responsibility to "look out for each other".
"Charity begins at home but it doesn't stay there. A strong family is generous to each other and to their neighbours and so it's here in our own country that we must learn to look out for each other and share whatever we can with those in need, here in the UK and overseas," he said.
"That's why the government should have honoured their promise to legislate for 0.7% of our country's income to help people in poor communities find their own ways out of poverty and build their families and communities to be strong, resilient and productive.
"I'm bitterly disappointed that we didn't hear that promise fulfilled today."