Christchurch: Thousands of vaccines are being delivered to health centres in New Zealand's Canterbury district as a measles outbreak has widened to 20 confirmed cases with health officials warning the number is expected to rise over the coming days and weeks.

Measles cases are rising globally, including in wealthy nations such as the United States and Germany, where some parents shun the vaccines mostly for philosophical or religious reasons, or concerns, debunked by medical science, that the vaccines against measles, mumps and rubella (MMR) could cause autism.

With Canterbury health centres running out of vaccines since the start of the outbreak in late February, 3000 MMR vaccines have been brought by Sunday and 18,000 more are to be delivered to the region by Wednesday.

New Zealand authorities are scrambling to provide enough doses of a measles, mumps and rubella vaccine. Credit:AP

"It can now be assumed that measles is circulating widely in our community," the Canterbury District Health Board said in a statement.