The singer's scheduled dates in the British capital were thrown into doubt when the former Smiths star left the stage at The Roundhouse on Friday (25Jan08) after performing just three songs.
After a 15-minute delay, it was then announced the 48-year-old could not continue with the show, the first of three at the venue.
As a result of the voice loss, Saturday's (26Jan08) and Sunday's (27Jan08) gigs will be rescheduled for a later date.
A statement from the star's representatives reads, "Morrissey's concerts scheduled for tonight and tomorrow night at The Roundhouse have been postponed due to illness.
"The iconic artist lost his voice last night five songs in to the fourth night of a run of six sold out shows at the legendary venue. He has been ordered by doctors to rest for the next four days."
Source: WENN