Port-au-Prince.– UN agencies and the Haitian government on Saturday prepared for a mass vaccination drive as potentially deadly diseases such as diarrhoea sprung up at squalid camps housing desperate quake survivors.

According to World Health Organization spokesman Paul Garwood, the vaccination campaign against measles, tetanus and diphtheria will start next week amid heightened efforts to prevent a potential public health calamity.

A vast foreign aid effort is struggling to meet survivors' needs more than two weeks after the disaster, which killed around 170,000 people and left one million homeless and short of food, water and medical attention.

"Several medical teams report a growing caseload of diarrhoea in the last two to three days.There are also reports of measles and tetanus, including in resettlement camps, which is worrisome due to the high concentration of people," Garwood said, adding that just 58 per cent of Haitian infants were immunized before the quake.