New Zealand is waiting too long to treat people diagnosed with HIV and the World Health Organisation believe it's not good enough.

New Zealand AIDS Foundation head Shaun Robinson said people can only access HIV medicines once the disease has already done a certain amount of damage to their immune system.

He said the World Health Organisation has released guidelines urging earlier intervention.

"If we can get this medication to people as early as possible so that their immune system is protected right from the beginning, then they're going to be much better off."

Shaun Robinson said the medication can also suppress the virus to a point where it is not as easily passed on, so there are benefits for the whole community.

He said research shows it keeps the individual healthier and dramatically reduces the chance of them passing on the virus.