The fit-again Alexia Putellas was handed a start by Spain coach Jorge Vilda and she played a part in early goals by Teresa Abelleira and Hermoso at Eden Park. Substitute Redondo then scored twice in the second half, either side of another Hermoso, goal as Spain cruised to victory.
Reigning Ballon d'Or Putellas, who recently returned from over nine months out with a serious knee injury, was taken off at half-time, with Vilda looking to preserve his star player for the Group C decider against Japan next Monday. Japan had beaten Costa Rica 2-0 earlier and they and Spain are now locked on six points each.
However, Spain's margin of victory means they now have a better goal difference and so just need a draw to finish in first place when the sides clash in Wellington. Zambia are already condemned to a first-round exit in their debut appearance at the World Cup after a second successive 5-0 hammering.
Putellas had made a series of cameo appearances for Barcelona in the final weeks of the season following her return from a ruptured anterior cruciate ligament suffered prior to last year's European Championship. She then started for Spain in a pre-World Cup friendly against Panama before appearing off the bench in last Friday's 3-0 defeat of Costa Rica.
Here she came in from kick-off, with Mariona Caldentey also handed a start by Vilda, the duo taking the Barcelona contingent in the Spain line-up to six.
Putellas handed start
Another Barcelona player, winger Salma Paralluelo, blazed an early chance over before Spain took a ninth-minute lead. Hermoso laid off a Putellas pass for Real Madrid midfielder Abelleira to blast high into the net from outside the area. It was 2-0 on 13 minutes as Putellas flighted a ball up from the left side of the box to the back post where Hermoso headed in.
Zambia, with the lively Barbra Banda leading the attack, had the majority of the crowd of almost 21,000 behind them but struggled to create chances. Putellas was cruising through the game, finding pockets of space in an inside-left role, but she did not reappear for the second half as Vilda made three half-time changes.
Her place was taken by Redondo, and the Levante forward got the third on 69 minutes, getting in front of Agness Musesa before rounding Eunice Sakala to score. The fourth goal arrived 60 seconds later, Hermoso converting the rebound after substitute Irene Guerrero hit the post, although the goal was initially ruled out for offside before being given after a VAR check.
Hermoso was denied a hat-trick when she saw a shot tipped onto the bar by Sakala, but Redondo got her second with five minutes left as she controlled Eva Navarro's cross before slotting in. Again the flag came up for offside, but again the decision was overturned on review.