Vatuvei took just nine minutes to get his first-half treble.
Johnson eclipsed that by requiring seven minutes to complete his in the second spell.
He also landed seven goals for a match haul of 26 points.
In all, the Warriors scored nine tries to three as they closed the door on Canberra's own finals ambitions, compounding the Raiders' off-field dramas of the past week and a half.
However, the visitors did have the last say, centre Jarrod Croker finishing off his own hat-trick three minutes from time.
Both teams were battling to keep their seasons alive and it was a tight encounter before the Warriors made it one-way traffic from late in the opening spell.
Down 12-10, the home side went on to score the next 40 points.
Vatuvei missed the birth of his third daughter, Eva, last weekend, after not being able get back in time from the Warriors' win over Gold Coast.
He seemed to have all the time in the world on Saturday by taking his try tally for the season to 15.
He began his first by defusing a bomb in his own half and was on hand to chase down Thomas Leuluai's kick into the in-goal.
The second featured quick hands, and a Feleti Mateo back-handed pass, as a group of Warriors worked a short-side play that ended with Vatuvei brushing past opposition fullback Reece Robinson.
The Kiwi winger completed his hat-trick two minutes from halftime.
He finished off an expansive backline move, with Robinson making a valiant but unsuccessful effort to stop him.
Johnson's opening try nine minutes into the second half highlighted his footwork and speed.
His second was a 70m intercept, while he chased his own grubber ahead for his third.
Johnson then laid on the pass for skipper Simon Mannering to touch down, before winger Ngani Laumape also got on the score sheet.
Earlier, the Warriors raced out of the blocks, a Leuluai short ball setting up second rower Elijah Taylor to score inside two minutes.
But the Raiders hit back with a Croker double, the first from a slick backline play.
Croker's second came when he swooped on a loose ball after Johnson's pass to no-one and sprinted 80 metres to dot down.
Croker added both conversions on the way to scoring all of his side's points.
WARRIORS 50 (S Johnson 3 M Vatuvei 3 N Laumape S Mannering E Taylor tries S Johnson 7 goals) bt CANBERRA 16 (J Croker 3 tries J Croker 2 goals) at Mt Smart Stadium.
Referees: Gavin Badger, Alan Shortall.