Skipper Ash Dixon's 22nd minute try from a rolling maul broke the deadlock, but Samoa hit back barely two minutes later.
First five-eighth Rodney Iona sparked the initial break, before finding winger Neria Fomai out wide on the left.
The scoreline remained at 7-7 until six minutes from halftime, when centre Billy Proctor's offload found Jonah Lowe who had too much pace for the cover defence.
The Māori All Blacks extended their lead right on the hooter, awarded a penalty try after Samoan flanker Sam Slade was yellow carded for a maul infringement