WELLINGTON (AFP) – New Zealand's national museum on Tuesday warned pregnant or menstruating women to stay away from some of its exhibits or risk an encounter with angry Maori spirits.

The Te Papa Museum in Wellington confirmed it had invited regional museum staff on a behind-the-scenes tour of its collections on the condition that women who were pregnant or menstruating did not attend.

The museum's Maori adviser Michelle Hippolite said the condition was because some of the Maori artifacts had been used in wars and were believed to contain sprits that could harm pregnant or menstruating women visiting the exhibit.

"They may have an encounter that may be a form of communication," she told Radio NZ.

"Those of us that are accompanying the group might not see this, hear it or understand what may be happening."

Te Papa spokeswoman Jane Keig said the policy was not an outright ban, rather it was strong advice designed to protect pregnant and menstruating woman from exhibits which Maori, New Zealand's indigenous people, believed could hurt them.

"Pregnant women are sacred and the policy is in place to protect women from these objects," she said.

Feminist blogger Deborah Russel said a taxpayer-funded museum should not force visitors to follow religious or cultural beliefs they may not share.

"I don't understand why a secular institution, funded by public money in a secular state, is imposing religious and cultural values on people," she told the New Zealand Herald newspaper.

"It's fair enough for people to engage in their own cultural practices where those practices don't harm others, but the state shouldn't be imposing those practices on other people."