WELLINGTON, March 12 (Xinhua) -- New Zealand's Health Minister David Clark on Tuesday urged people to ensure their vaccinations are up to date as more MMR (measles, mumps and rubella) vaccine is sent to Canterbury in the South Island to deal with the ongoing measles outbreak.

A total of 18,000 extra doses of the MMR vaccine are being transported to Canterbury over the next 24 hours. They will be available for use from Wednesday. Further supplies of the vaccine will follow, Clark said in a statement.

There have now been 25 confirmed measles cases in Canterbury, and this number is expected to rise, Clark said, adding vaccination is the best protection against this serious and highly infectious virus that spreads very easily from person to person.

"The MMR vaccine is very effective and it's free," he said.

"Children who have not yet been immunized are at the greatest risk from the disease, so it's important to make sure you and your family are up to date with their immunizations," the minister said.