Here are some options, depending on the context:
For a safe as in a secure place:
* Whare taonga: This literally means "treasure house" and could be used for a safe.
* Whare mārama: This means "bright house" and implies a place that is well-protected.
For a safe as in the concept of safety:
* Haumaru: This is the most common word for "safe" in the sense of being secure or protected.
* Te tiaki: This means "protection" or "care" and could be used to describe a safe as a protector of valuables.
For a safe as in a specific device:
* Pouaka whakaora: This literally means "rescue box" and could be used to describe a safe for storing valuables.
* Pouaka tiaki: This means "protection box" and could also be used for a safe.
Ultimately, the best way to say "safe" in Māori depends on the specific context and what you are trying to convey.