Cavan-native Leanne Kiernan was named the Three Player of the Match following her fantastic brace and skipper Katie McCabe added a further two to make it a comfortable 4-0 victory.
It only took Colin Bell's side three minutes to get on the scoresheet as Diane Caldwell's lofted 40-yard ball found the explosive Kiernan who chipped the ball neatly over keeper Jacqueline Burns.
Northern Ireland struggled to settle with the pace of Kiernan and the strength of Rianna Jarrett up front, and with 11 minutes gone, Ireland doubled their lead. Kiernan stretched the Northern Ireland defence down the right before Tyler Toland's long-range was parried and after Jarrett's neat lay-off, Katie McCabe powered the ball home.
The Tallaght Stadium crowd were treated to a third goal in the first 30 minutes when Kiernan notched her second of the game. Jarrett was once again involved as she found Denise O'Sullivan who found the perfect pass to Kiernan and the West Ham Ladies striker finished with aplomb.
President Michael D Higgins was in attendance for the second time during the campaign and Ireland sealed their fourth win in the group in the second-half. Harriet Scott latched onto an O'Sullivan through-ball before keeper Burns conceded a 56th-minute penalty. Captain McCabe stepped up to score her second of the game, the spot-kick neatly placed to the keeper's right.
Ireland continued to dominate the occasion and Kiernan almost bagged her first senior international hat-trick four minutes from the end, but could only find the up-right from eight yards out.
Colin Bell handed a senior international debut to Shelbourne Ladies striker Jessica Ziu in the second-half. The 16-year old replaced Wexford Youths striker Jarrett as preparations begin for next year's UEFA 2021 European Championships qualifying campaign.
"It was a fantastic performance. To get goals like that in the opening stages of the game really settled us and I was extremely happy with the quality of the finishing tonight," WNT Head Coach Colin Bell said.
"Leanne Kiernan is beginning to really show what she can do. Her pace will always get her in threatening positions but it's always been about her using those positions well. Her progression in the past year has been fantastic, all the hard work put in at Shelbourne Ladies and now, West Ham, it is paying off.
"We'll sit down tomorrow as a group and go over the game, and go through the lessons we've learnt throughout the campaign. There will be certain moments which stick out in the last year or so, and which we can improve. We're heading in the right direction though and the players have to keep that up."
The WNT face a trip to Poland on Tuesday, October 9 in an international friendly match with further plans for the rest of the year and early 2019 to be confirmed. Ireland finished third in Group Five with just European Champions the Netherlands and top seeds Norway set to finish ahead of them.
Republic of Ireland: Amanda Budden (GK), Heather Payne, Harriet Scott, Louise Quinn, Niamh Fahey, Diane Caldwell, Leanne Kiernan (Amber Barrett 87), Denise O'Sullivan, Katie McCabe (C), Tyler Toland (Karen Duggan 60), Rianna Jarrett (Jessica Ziu 75).