A New York county has banned unvaccinated children from public spaces for the next 30 days admits a measles outbreak.

A state of emergency has been declared in Rockland County in an effort to contain the spread of the disease.

Rockland County Chief Executive, ED Day, told Kate Hawkesby it was an extreme measure but it was necessary.

"We've spent six months dealing with this outbreak, initially we were making great strides."

However, Day says the immunisation effort was met with huge resistance from anti-vaxxers.

"We were looking to minimise exposure and maximise immunisation and we got about 17,000 immunisations done but even with that, we were still having an increasing number of cases."

"The problem we are having now is two-fold, in addition to the increasing cases. We are running into resistance in some quarters for people to get their children vaccinated."

"When we tried to find out what kind of movement infected people have, so we can warn others what they should be in the lookout for, we were being met with doors being slammed in our faces...and people refusing to work with us."

The upcoming Easter and Passover celebrations are also causing concern, he said.

The vaccinations are free in the County.

Ed Day said people have forgotten how awful the disease is so they are less likely to vaccinate.

"When the vaccine first came out 2.6 million people died from measles, in 2017 that number was cut by 97 per cent."

"It [measles] can also cause blindness, eye damage, hearing...there are a lot of things that can happen from measles even if it's not death, and the ones most at risk are children."

He said he can understand that people might have concerns about vaccinations, the science shows, by in large, the MMR vaccine is safe and effective.

"We have to concern ourselves with everybody around us...measles is a contagious disease, the contagion can last for up to two hours on a handrail."