The discovery of a deadly plant disease in Northland has sparked fears for New Zealand's most sacred tree.

The weather-beaten pohutukawa that clings to the rocks at the tip of Te Rerenga Wairua, or Cape Reinga, is regarded as the gateway to the underworld, Te Hinenui o te Po. From there the spirits of the dead are said to begin their long journey back to Hawaiki.

Pohutukawa, like rata and manuka, are members of the myrtle family, so could be affected by myrtle rust, the plant disease found in Kerikeri last week.

Ngati Kuri Trust Board chairman Harry Burkhardt said his iwi, the country's northernmost, had serious concerns for the Cape's pohutukawa.


The iwi was working with the Department of Conservation (DoC) and planning to inspect the tree for signs of the fungal disease, though access to the steep and rocky site was difficult.

There were also concerns for the manuka honey industry, which the trust board and whanau were involved in and had become an important part of the Tai Tokerau economy.

Mr Burkhardt said he did not wish to be alarmist because it was not yet clear what effect the disease would have on New Zealand members of the myrtle family. In Australia it had devastated some species and had little effect on others.

"We have teams working right up the top of the island and they're all alert to the risk. There was an inevitability about it [myrtle rust] coming here. The question is, how do we adapt?"

Te Paki, the northern tip of Northland, is also home to New Zealand's rarest tree, Bartlett's rata or rata moehau. Rata are potentially also vulnerable to myrtle rust.

All 14 Bartlett's rata on the planet are found in three stands of bush near Spirits Bay.

Rolien Elliot, who is heading DoC's response to myrtle rust, said the three sites had been checked by DoC staff who found no sign of the fungal infection.

Signs had been put up to warn people not to enter the fenced-off areas around the trees, and DoC staff were carrying out weekly checks.


Ms Elliot said DoC's Kaitaia office was also working with Ngati Kuri to check the "special and significant" pohutukawa at Cape Reinga. Those checks, however, presented challenges due to the inaccessibility of the site.

Meanwhile, about 100 staff from the Ministry for Primary Industries, DoC, AsureQuality and the Northland Regional Council are continuing ground inspections and tracing customers of Kerikeri Plant Production, where the fungus was first found.

As a result rust-like symptoms were found at a South Auckland nursery, which had bought plants from the Kerikeri nursery, but lab tests came back negative late yesterday.

Temporary biosecurity controls placed on the South Auckland nursery had been lifted, MPI's response director Geoff Gwyn said.

As of yesterday the disease had been confirmed at only two sites, the original nursery and a neighbouring garden. Re-testing of samples from a second Kerikeri nursery was also negative.

The fungus is spread on the wind, clothing, tools or footwear by tiny spores. It has been present in Australia since 2010 and is thought to have blown over to Northland.


■ Myrtle rust can also infect feijoa, gum and bottlebrush trees, and garden plants such as lilly pilly. If you see anything suspicious, don't touch it but take a photo and call MPI on 0800 809 966.