The agencies, including World Vision, Action Aid, Save the Children and Relief International, said in a joint statement issued on the eve of a London conference for Somalia that lending restrictions are hampering Mogadishu's efforts to scale up investments in education, health and security sectors.
"Cancelling the debt would give Somalia access to long-term development finance and create the conditions for private investment," the organizations said.
International Monetary Fund (IMF) Managing Director Christine Lagarde in January pledged to prioritize Somalia's debt relief, saying every effort is being made to speed up the process.
According to the IMF, Somalia's external debt is about 5 billion U.S. dollars, but Mogadishu has not made a service or amortization payment since the onset of the civil war two decades ago, making it impossible to access loans from the IMF.
The agencies said the countries that are in arrears to the IMF and the World Bank are not eligible for debt relief, nor can they receive funding through the World Bank's International Development Association (IDA).
"These arcane rules on arrears are excluding Somalia from one of the largest development financing pots. As many policy influencers gather in London, they have an opportunity to change this picture," said the agencies.
They said many children's lives could be saved with well-functioning health, education services and safety nets that are well catered by a stable government and its institutions.
The focus of the High-Level Event for the Humanitarian Situation in Somalia is to draw attention to the humanitarian crisis in Somalia and generate political and financial momentum for the 2018 humanitarian response and recovery.
Somali Prime Minister Hassan Khaired is in the United States for meetings with IMF and World Bank officials as Mogadishu seeks to have its debt cancelled.