Holmes said international aid efforts were making "significant progress" since a visit to Myanmar by Ban Ki-moon, the UN secretary-general, which persuaded the country's military rulers to free up access for relief workers.
Myanmar's government was heavily criticised in the critical early days immediately after the cyclone for blocking access to international relief workers and supplies.
Cyclone Nargis struck Myanmar in early May and left more than 138,000 people dead or missing.
The UN says 2.4 million people have been seriously affected by the cyclone, and remain in need of long-term aid.
More than 100 projects are planned to deliver food, shelter, clean drinking water, sanitation, education and other needs.
Holmes said that in the wake of the cyclone 1-in-2 families in Myanmar have food supplies of only about one day or less, while some 60,000 children were at risk of malnutrition.
He said the cyclone wiped out 42 per cent of the nation's overall food stocks.
An estimated 84,000 people were killed in the May 2-3 storm, with more than 53,000 still officially listed as missing.