While assessing the damage along the southern coast of Upolu, which bore the brunt of Wednesday's tsunami, Mr Clark said he did not like what he saw.
"There is a lot of damage... and there is a lot of work to be done, both in the short term and the long term."
Mr Clark said fales were flattened, boats upended and vehicles and vegetation crushed.
Mr Clark, who has more than 30 years of experience with the Red Cross, said the devastation in Samoa was not as widespread as that of the 2004 Boxing Day tsunami, but devastating nonetheless.
Of the 180,000 people living in Samoa, 26,000 are believed to be directly affected by the tsunami.
The New Zealand Red Cross is assisting with the disaster recovery after being invited by the Samoan Red Cross.
Arriving in Apia courtesy of a New Zealand Defence Force C130 Hercules, Mr Clark said he was "running on adrenalin" since he heard reports of the earthquake and tsunami.
Part of his role was to assist the Samoan Red Cross and its 200 volunteers.
As part of that response, a commercial flight containing 50 family tents, 1000 blankets, 500 kitchen sets and 200 body bags arrived in Apia yesterday.
How to help
> Red Cross: online at www.redcross.org.nz; cheques to the Samoan Earthquake and Tsunami Appeal, Red Cross House, PO Box 12140, Thorndon, Wellington 6144; automatic $20 donation 0900 31 100; Westpac branches.
> Oxfam NZ: online at www.oxfam.org.nz; phone 0800 400 666; automatic $20 donation 0900 600 20.
> Caritas Aotearoa: online atwww.caritas.org.nz; phone 0800 221 022; automatic $20 donation 0900 411 11; cheque posted to Caritas, PO Box 12193, Wellington 6144.
> ANZ branches
