Canadian and British researchers are suggesting there should be a global ban on a commonly used painkiller.
An article in the open access journal PLOS Medicine says the use of diclofenac, sold in New Zealand as Voltaren, increases the relative risk of a heart attack or stroke by between 40% and 60%.
The study found that although the risks of Voltaren have been known for several years it is still prescribed far more often than safer drugs with similar effects.
The director of the national stroke centre at AUT University, Valery Feigin, supports the call for a ban.
Dr Feigin says the increased risk is not a problem for athletes who use Voltaren for aching muscles but is more serious for older people who use it for joint pain.
Drug safety regulator Medsafe says a review in 2008 found its benefits outweighed the potential danger for most patients.
However it says it will discuss the latest study with its expert advisory committee.