Medical experts are recommending the vaccination of adults, including expectant parents, to combat a surge in cases of whooping cough in NSW.

Whooping cough notifications increased from 696 between January and March last year to 5444 for the same period this year, Health Minister John Della Bosca said.

"I urge new parents, grandparents and adults who regularly care for infants less than 12 months old to get vaccinated against whooping cough," he said.

The condition, which is preventable but can be fatal, is most commonly diagnosed in children younger than six months, said Ken Peacock, the head of paediatrics at the Children's Hospital at Westmead.

"This is certainly a significant surge," Dr Peacock said.

Children are usually given a fourth dose at four years old and another in their late teens, but immunity typically wanes after 10 years. Free booster vaccinations are available from GPs across NSW.

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