The OCC's Martin Talbot said: "The public have clearly taken the plight of the Haitian people to heart - this record is huge."
HMV spokesman Gennaro Castaldo added: "It's already the biggest seller of the year so far, and is now likely to go on to be the number one single of 2010."
Elsewhere in the singles chart, the cast of Glee notched up another top 10 hit with their medley of Halo and Walking On Sunshine, in at nine.
Their cover of Don't Stop Believin' is in fifth place, while another mashup from the hit TV show becomes a new entry at 14.
In the album chart, Alicia Keys' The Element of Freedom remains at number one, with Andre Rieu's collection of Viennese waltz music still in second spot.
Sade's comeback album Soldier of Love enters the rundown at four, with Heligoland by Massive Attack new at six.
Albums from Michael Buble and the Black Eyed Peas enjoyed a resurgence, clambering back into the top 10.