Samantha Kudeweh (43) was killed by one of the zoo's tigers, Oz, on September 20.
The Hamilton City Council, which owns the zoo, is remaining tight-lipped on how the attack happened but council chief executive executive Richard Briggs would only comment that staff are not supposed to be in the same enclosure as tigers.
The service is being held at the Hamilton Gardens.
Mr Briggs earlier said he was expecting a large turnout, including zoo professionals from Australia and around the world.
The Kudeweh Family Trust's givealittle page, set up to support her two young children and husband, has so far raised more than $20,500.
Mr Briggs confirmed there were no plans to send Oz to another zoo, as he was integral to the tiger breeding programme.