"We are currently in Western Visayas in the middle of the typhoon's path. The devastation is beyond our expectations,'' he said.
"Right now you can see houses destroyed, people are homeless, sink-holes and cracks in the ground have destroyed roads.''
Communication was limited as many powerlines had also been destroyed.
Mr de Leon is in contact with Tear Fund's New Zealand-based group and called on Kiwis to help with their efforts.
"Our team mobilised immediately and is currently on the ground delivering food supplies of rice and canned goods in the worst hit relief areas.
"We have the expertise and capacity to save lives, but we need the help of Kiwis to do so.
Our local partners are already responding but we need your help to continue this work.''
To donate, go to: www.tearfund.org.nz
- Govt donates further $2m-
Meanwhile the Government has given a further $2 million to help the Philippines in the aftermath of Typhoon Haiyan, and Prime Minister John Key has offered to delay his scheduled trade delegation trip to Manila next week.
Thousands of people are feared dead after the typhoon hit the central Philippine islands last Friday.
Foreign Minister Murray McCully yesterday announced a further $2 million on top of the $150,000 for the International Red Cross.
Mr Key was due to visit Manila next week with several businesspeople after going to Sri Lanka for the Commonwealth Heads of Government meeting (Chogm). He said he had asked the Philippines government if it wished to postpone his visit.
"I wish to offer President Aquino and the people of the Philippines New Zealand's heartfelt condolences at the tragic loss of life. We remain committed to helping wherever we can," the Prime Minister said.
He said he would go ahead with a visit to Thailand on the way back from Chogm.
Mr McCully said the typhoon had affected more than 4.4 million people across 36 provinces in the Philippines and almost half a million had had to leave their homes.
He said $750,000 was allocated to match funding from agencies working to support the relief and initial recovery effort while the remaining $1.25 million would be allocated to priority areas.
A New Zealand aid worker was working with the United Nations Disaster Assessment Co-ordination team integrating the international effort.
To donate
Red Cross: redcross.org.nz
World Vision: worldvision.org.nz
Unicef New Zealand: unicef.org.nz
Tear Fund: tearfund.org.nz
Save the Children: savethechildren.org.nz
Oxfam: oxfam.org.nz.
Where to go for help
*The Ministry of Foreign Affairs advises all New Zealanders in affected areas to follow the advice of the local authorities and keep family and friends at home informed of their safety.
* For consular assistance, contact the New Zealand Embassy in Manila on +63-2-891-5358.