Britain has promised £28 million of aid to Yemen but warned that the major terror attack which killed 96 soldiers underlined the risks of an even greater humanitarian crisis.
Al Qaida in the Arabian Peninsula claimed responsibility for Monday's suicide bomb which soldiers rehearsing for a parade in the capital Sana'a.
It came ahead of a meeting in Saudi Arabia of the international Friends of Yemen group - which is co-chaired by the UK. Among those attending will be International Development Minister Alan Duncan who is to give details of the package of help for the country.
Existing extreme poverty has been worsened by the violence, with around half a million people being displaced and nearly a million under-fives malnourished.
Mr Duncan said the aid - to be delivered via established NGOs and agencies - would provide a "foundation for progress" as well as immediate help.
But he cited the the terror attack as a stark reminder of the risks of a slide into an even more serious humanitarian crisis. "The new government of Yemen has been in place for a matter of months and has already taken important steps. But (Monday's) terrible suicide bombing reminds us that the country still faces huge challenges," he said.
"If progress is to be maintained then the international community must back the government. Without that support, the alternative is a slide towards state failure and an increased threat from international terrorism.
"Yemen's partners and the wider community must respond to this humanitarian crisis but also deliver longer term support to address the root causes of the problems the country faces and help it start to rebuild after years of internal conflict and political instability."
Officials said the aid could mean emergency food for up to a quarter of a million people as well as safe water sources, shelter and healthcare for those fleeing the violence. It could also help fund education for 60,000 children in conflict zones and pay for goods and labour to support 35,000 adults.
Foreign Office Minister Alistair Burt, who will also represent the Government at the Friends meeting said: "This cowardly attack must not be allowed to stall or prevent progress towards the completion of rigorous reform. As we prepare to meet in Riyadh ... we are resolute in our support for President Abd Rabbuh Mansour Hadi as he leads his nation towards a safer and more prosperous future."