Winiata's second was the result of a concerted build-up and nice passing. She may have had a third, but, after a scything break, was lowered in a copybook grassing tackle by Ireland centre Sene Naoupu, wife of current Harlequins and former Canterbury loose forward George Naoupu.
Woodman was her usual self at centre, punishing without the ball and electric with it, her second try a superb long-range solo effort.
The final try went to No 10 Kelly Brazier, who showed all her fancy footwork after a bullocking charge from young replacement prop Aotearoa Mata'u.
Ireland scored a fine consolation try in the 82nd minute to replacement back Niamh Kavanagh.
Standouts for the Black Ferns were Woodman, Winiata and halfback Kendra Cocksedge, around whom so much of their play is built, and blindside flanker Charmaine Smith, who was prominent in the lineouts, mauls and around the field, while Mata'u offered maximum impact off the bench.
The Black Ferns also won tight victories over England and Canada on the tour, and the three tests in eight days acts as perfect preparation for next August's World Cup, in which there will again be a tight schedule. The UCD Bowl, venue for this morning's international, will be one of the stadia used at the World Cup.
Woodman and Brazier will now fly to Dubai to link up with the Black Ferns Sevens, who open their World Series campaign on Thursday night (NZT).
The Black Ferns will next play in June, in an intense lead-up programme that is yet to be announced by New Zealand Rugby.
Black Ferns 38 (Portia Woodman 3, Selica Winiata 2, Kelly Brazier tries; Kendra Cocksedge 3 con, Hazel Tubic con) Ireland 8 (Niamh Kavanagh try; Nora Stapleton pen)
HT: 5-3