The American Red Cross said on Thursday it had received $18 million while Care USA said it received more than $3.5 million from the public.
Care spokeswoman Lurma Rackley said the group had also received a donation of more than $2 million from the Pfizer pharmaceutical company.
Newspapers list organisations collecting money for the Asian victims while stores, coffee shops and restaurants, particularly those run by Asian immigrants, have launched their own fundraising initiatives.
At the New York Gourmet diner in the centre of Washington, many of the staff come from Indonesia, and a simple cardboard box has been left at the cashier's desk for customers to leave cash.
"We have not counted it yet," said cashier Adeline Yosephine, who comes from Jakarta. Her colleague, Icha Sulaiman, said the money would be sent to the Indonesian embassy where long queues of people have signed a book of condolences.
The popular fundraising initiatives come a few days after President George Bush and Secretary of State Colin Powell bristled at suggestions by UN chief disaster relief coordinator Jan Egeland that rich countries were "stingy" in giving aid.
Scenes of carnage have moved
the US public to aid funding
Egeland has insisted his comments were misinterpreted and not pointed at the reaction of the US or other countries to Sunday's tsunami disaster. Bush has still said the comments were "ill-informed", however.
But the New York Times countered with an editorial on Thursday which said the US has indeed been "stingy".
"We beg to differ [with Bush]. Mr. Egeland was right on target," the paper said.
"But the $35 million remains a miserly drop in the bucket, and is in keeping with the pitiful amount of the United States budget that we allocate for non-military foreign aid," it added.
The Times chided Bush for waiting until Wednesday to express his sympathy to leaders of India, Sri Lanka, Thailand and Indonesia for Sunday's disaster that has left an estimated 120,000 people dead and millions homeless.
The president announced the increase in US aid to $35 million on Wednesday, saying it was "only the beginning".
The daily added that it hoped Secretary of State Colin Powell was embarrassed to announce "the initial measly aid offer" of $15 million.
"That's less than half of what Republicans plan to spend on the Bush inaugural festivities," in January, it said.
Corporate America helps
Corporate America has also joined the fundraising.
Internet search engine Google
now has a section for tsunami aid
Oil giant ExxonMobil said it had given $5 million and banking bigwig Citigroup, which has a large network in Asia, $3 million.
Many people are giving money through the internet. The Google search engine has put a "ways to help with tsunami relief" section on its normally sparsely filled opening page.
A click on the link takes surfers to the sites of several humanitarian organisations such as Oxfam and Medecins sans
Frontieres (Doctors Without Borders).
Online retail company Amazon.com has linked up with the American Red Cross to collect money from the public. It said more than 75,600 payments totalling $4.6 million had been made by midday Thursday.
Private donations in the country will soon match the $35 million that the US government has so far donated to the relief effort.