The visitors fought back after half-time, Evans barging over beside an upright four minutes after the resumption, Elinor Snowsill knocking over the additional two points.
Two minutes later number eight Harries rolled away from an attempted Irish tackle, broke clear and raced over the line to put two points between the teams.
Prop Lindsay Peat was shown a yellow card for a high tackle earlier in the move but despite being a player down Ireland soon scored their third try, Briggs switching the ball to the impressive Naoupu, who powered her way over.
Flanker Molloy dotted down again soon after but the referee had already blown for an infringement and the try was disallowed.
The bonus-point try arrived with six minutes remaining, Naoupu providing the pass for Tyrrell to dummy and score, before Molloy displayed a burst of searing pace to dive over for her side’s fifth try with 79 minutes on the clock.
Ireland: Kim Flood; Megan Williams, Katie Fitzhenry, Sene Naoupu, Claire McLaughlin; Niamh Briggs, Ailsa Hughes; Lindsay Peat, Ciara O’Connor, Leah Lyons; Orla Fitzsimons, Aoife McDermott ; Ciara Griffin, Claire Molloy (capt), Paula Fitzpatrick.
Replacements: Cliodhna Moloney, Laura Feely, Fiona Reidy, Elaine Anthony, Edel McMahon, Nicole Cronin, Michelle Claffey, Hannah Tyrrell.
Wales: Lisa Neumann, Hannah Bluck, Kerin Lake, Rebecca De Filippo, Jess Kavanagh-Williams, Elinor Snowsill, Rhiannon Parker, Caryl Thomas, Carys Phillips, Amy Evans, Siwan Lillicrap, Mel Clay, Alisha Butchers, Beth Lewis, Sioned Harries.
Replacements: Kelsey Jones, Cara Hope, Meg York, Natalia John, Nia Elen Davies, Jade Knight, Robyn Wilkins, Hannah Jones