A breakthrough treatment that could save babies from a deadly but preventable lung disease is sitting in the hands of Pharmac - and respiratory health experts say there's no time to waste.

Last week, it was revealed that nirsevimab - a monoclonal antibody against respiratory syncytial virus (RSV) - is under consideration by both Medsafe and Pharmac for the prevention of RSV in infants.

The Asthma and Respiratory Foundation NZ has long advocated for access to RSV protection, after years of high hospitalisation rates among infants - particularly in Māori and Pacific communities.

Foundation Chief Executive Ms Letitia Harding says the potential approval of nirsevimab could be a game-changer.

"This is the progress we've been waiting for.

"RSV hospitalises thousands of children every year, and this treatment has the potential to prevent many of those admissions."

However, Pharmac needs to act quickly to ensure it is ready for the 2026 season, Ms Harding says.

"We can't afford delays if we want to save lives of some of our most vulnerable.

"We're urging decision makers to prioritise funding so that New Zealand infants can benefit as soon as possible."

Unlike the existing option, palivizumab, which requires monthly hospital visits for high-risk infants only, nirsevimab is a single injection that can be given by GPs, nurses, pharmacists or midwives. It provides protection for an entire RSV season and can be offered to a broader group of babies.

Foundation Medical Director Professor Bob Hancox says the opportunity to introduce a more effective and accessible RSV immunisation is a critical step for child health.

"RSV is one of the most common and serious respiratory infections in infants, and it places enormous strain on our hospitals every winter.

"This new treatment could dramatically reduce hospitalisations and health inequities," he says.

"New Zealand must move quickly to make it available."