Do banks in New Brunswick require probate before releasing money?

This answer covers the law of New Brunswick.

Not always, but a bank will usually want proof that you have authority to deal with the account. Probate is not strictly mandatory in New Brunswick, though it is recommended, especially when the estate includes real property. On death, the deceased's property vests in the personal representative, which is why a third party dealing with assets will usually ask for proof of that person's authority.

The proof is typically letters probate where there is a will, or letters of administration where there is no valid will. If the grant comes from another jurisdiction, it may need to be sealed by the Probate Court first, once the required tax is paid. For smaller estates, where the probate value does not exceed $25,000, the Public Trustee does not need to be appointed by the Court and may administer after filing an affidavit with the Registrar.

Which balances a bank will release without a grant, and which documents it asks for, depends on the bank and the account, so ask the bank directly. You will likely need a death certificate, which you can order through Vital Statistics. A lawyer can help you decide whether applying for a grant makes sense.