Health professionals and campaigners on Thursday stepped up pressure on the New Zealand government to introduce a sugar tax, following the surprise announcement of such a tax in the United Kingdom.

The New Zealand Medical Association said the UK government's plan to tax sugar-sweetened beverages was one of a suite of measures it recommended the New Zealand government consider to address obesity.

"This is an important step in protecting the health of children," NZMA chair Dr Stephen Child said in a statement. "We reiterate our call for the New Zealand government to consider taking a similar step to protect the health of New Zealand children, the most vulnerable in our community."

In a 2014 policy briefing, the NZMA asked for priority to be given to consideration of a tax on sugar sweetened beverages.

The opposition Green Party said the New Zealand government's inaction on obesity stood in stark contrast to the "brave action" of UK Chancellor George Osborne.

New Zealand Health Minister Jonathan Coleman had repeatedly refused to introduce a similar levy, despite advice to do so by the prime minister's chief science advisor and other experts, Green Party health spokesperson Kevin Hague said.

"It's time for the Health Minister to follow the UK's lead and put the health and wellbeing of children ahead of the interests of the junk food industry," Hague said.

"All the evidence shows that sugar is damaging the health of New Zealand children and is driving our obesity epidemic. It's time for the Minister of Health to put children first and take this simple step to protect them."

Coleman told Radio New Zealand on Thursday that the government had not altered its position on a sugar tax, and it was not actively considering it.

The government would keep an eye on emerging science, but there was no single solution to obesity, he said.

The UK's sugar levy was announced in Osborne's annual budget, when he said, "I am not prepared to look back at my time here in this Parliament, doing this job and say to my children's generation... I'm sorry. We knew there was a problem with sugary drinks. We knew it caused disease. But we ducked the difficult decisions and we did nothing."