Diabetics who have been diagnosed with bladder cancer after taking a particular medication are being urged to join legal action against the pharmaceutical company.
The drug Pioglitazone - more commonly known as Actos or Pizaccord - is funded by the Government and is used to treat type-2 diabetes.
It improves the body's ability to use insulin, leading to better control of blood sugar levels and helping avoid diabetes complications.
It has been funded since 2004 and about 4000 New Zealanders were prescribed the tablets last year, according to Pharmac.
Studies linking Pioglitazone to bladder cancer have sparked legal action in the United States against the Japan-based co-manufacturers and distributors Takeda and US giant Eli Lilly.
Australian-based law firm Maurice Blackburn Lawyers have also lodged a claim in the United States on behalf of a Brisbane man, who was diagnosed with bladder cancer two years after he started taking the medication.
The firm is now calling for New Zealand diabetics to join the legal action if they have been diagnosed with bladder cancer after taking Pioglitazone, Maurice Blackburn principal Damian Scattini said.
"The makers of this drug have known for some time about an increased risk of bladder cancer, but in spite of this they have still failed to provide appropriate warnings to people and doctors in Australia and New Zealand about prolonged use in patients with type-2 diabetes."
The interim findings of a 10-year study show that patients taking the tablets for more than 12 months had a 40 per cent increased risk of bladder cancer, Mr Scattini said.
Safety warnings have been issued by the United States' Food and Drug Administration and Australia's Therapeutic Goods Administration.
The drug has also been withdrawn from sale in France and Germany.
Diabetes New Zealand said people should not stop taking the medication and those with concerns should speak to their GP.
MedSafe's Medicines Adverse Reactions Committee last reviewed the safety of Pioglitazone in 2011.
A warning about bladder cancer was added to the data sheet.
There were no reports of bladder cancer.
Resource consent being denied for the Basin flyover is:Related story: Board of inquiry says 'NO' to Basin flyover