A sacred archaeological area of Ōwairaka/Mt Albert in Auckland has been damaged, after 27 trees were found to have been planted into the site illegally.

The disturbed area was previously unmodified, meaning it was in the original form of the maunga dating back near 1000 years to a preserved historic pā settlement.

At one section the planting spans a historic pā terrace and there is also evidence of disturbed midden, or ancient shell deposits, dating to the pā site.

Given the historic significance of Ōwairaka, any illegal modification is prosecutable under the Reserves Act 1977 and the Heritage New Zealand Pouhere Taonga Act 2014. The damage has been reported to Heritage New Zealand.

Paul Majurey, chair of the Tūpuna Maunga Authority, said the sacred site at Ōwairaka appears to have been deliberately altered with a large area around the planted trees treated with herbicide, deepening the damage to the maunga.

"The management of the Maunga is guided by the spiritual, ancestral, cultural, customary, and historical significance of the Maunga to Ngā Mana Whenua o Tāmaki Makaurau," he said.

"This means, as part of the Authority restoration programme we look at all these factors – ensuring the least damage to the archaeology of the maunga as possible."

There is evidence of disturbed midden, or ancient shell deposits, dating to the pā site. Photo / Supplied

"It is tragic that there are people desecrating this ancestral maunga and taonga in complete disregard to cultural significance," Marjury said.

"When undertaking the authority's planting programme, the team work closely with archaeologists and other experts to ensure planting is managed, properly included, engaging authority to modify from Heritage New Zealand, if necessary.

"We have a zero tolerance of unauthorised digging on the maunga and anyone found responsible for such activity will be prosecuted. We are seeking information from anyone who might know something about this."

Similar damage occurred on other Auckland maunga and historic sites. Ōtāhuhu/Mt Richmond in October 2018 and Takarunga/Mt Victoria in September 2019.