Rates of the deadly disease whooping cough have soared in New Zealand in the past three years, with thousands more people infected.
The 2012 rate was 122.3 cases per 100,000 people - more than two and a half times the 45.4 in 2011 and more than six times the 20 in 2010.
Last year 5938 notifications were recorded, nearly 4000 more than the 1996 notifications in 2011, according to the latest Public Health Surveillance report on the disease.
During this period, 309 hospitalisations and two deaths were reported.
Last year, the region with the highest number of cases was Nelson Marlborough, followed by the West Coast and Wairarapa.
Out of more than over 1600 cases where a patient's vaccination status was known, 589 were not vaccinated.
Of those cases hospitalised, more than 20% were from the Pacific Islands, 14.5% were Maori, compared to just under 4% European and 8.5% classified as "other", the report said.
Of the cases reported last year, infants less than one year old had the highest notification rate with 414 cases reported. For children aged 1-4 years 892 cases were reported, with more than 700 cases reported for children aged 5-9.
Whooping cough is common in New Zealand, according to Ministry of Health data, with the country having an outbreak of the every three to five years.
"The most recent outbreak began in August 2011 and is still ongoing," the ministry said on its website.
"Since the outbreak began more than 6700 cases of whooping cough have been reported."
The ministry said that during the 2004-2005 epidemic, more than 5000 cases were reported. In 2004, 159 children were hospitalised, and one child died.
Whooping cough is a highly infectious disease spread by coughing and sneezing, and caused by bacteria which damages the breathing tubes.
The ministry said the cough started with cold-like symptoms, such as a runny nose, sneezing, a slight fever, and a mild cough.
"The cough becomes worse and can make you or your child vomit," it said.
"Babies and children often gasp for air and some make a 'whooping' sound during coughing attacks.
"Most children can seem well between the coughing spells."
The disease could lead to pneumonia, brain damage, convulsions and death.
The ministry said if someone had a suspected case of whooping cough, they should go to the doctor as soon as possible and stay away from others.