Lionesses boss Sarina Wiegman missed her side's final group game after testing positive for COVID-19, but the hosts made another statement at St Mary's Stadium on Saturday (AEST).
First-half goals from Fran Kirby and Beth Mead set England on its way, as it became the first team to score more than 10 or more goals in the group stage of a women's Euros without conceding.
Alessia Russo scored England's third just minutes after coming on at half-time with an excellent header and helped herself to a brace in the 53rd minute, when an exquisite turn on the edge of the box made the space for her to lash home and make it 4-0.
Kelsie Burrows summed up a miserable night for Northern Ireland when she scooped into the back of her own net.
The Group A winner will face the runner-up in Group B on Thursday (AEST) for a place in the semi-finals.
Norway headed into its final group game knowing that only a win would see it through, because of its inferior goal difference after an 8-0 thumping at the hands of England last week.
Austria only needed a draw, and went ahead after 37 minutes when a superb header from Nicola Billa nestled into the bottom corner.
Martin Sjogren's side was unable to respond, so Austria will face Germany in the last eight at Brentford Community Stadium on Friday (AEST) and Norway heads home after a more than disappointing campaign.
