Sweden are already into the knockout phase of the Women's World Cup but are eager to maintain their winning momentum in Wednesday's final group game against Argentina, captain Magdalena Eriksson declared.

Sweden secured their last-16 spot with a 5-0 destruction of Italy on Saturday, following a comeback to beat South Africa 2-1 in their opening game.

Those results mean they have almost certainly sewn up top spot in Group G, with their superior goal difference meaning that even a defeat against Argentina is unlikely to knock them off the summit.

But Eriksson, one of three captains in the Swedish squad, said her team would not relax against the Argentines in Hamilton.

"It's very important. The match on Saturday was not perfect. We can do a lot better, we have a lot to learn," said Eriksson, whose central defensive partner Amanda Ilestedt has scored three goals in the two games so far.

She said Colombia's stunning win over Germany serves as a warning of what to expect from South American opposition, especially with Argentina having to win to stand a chance of advancing.

"We are confident, but also very humble. Tomorrow will be a tricky task, as we saw with Colombia beating Germany."

Swedish coach Peter Gerhardsson has named the same starting line-up in both previous games at this World Cup but hinted he might make changes with a last-16 tie looming on Sunday.

"You should never assume when you have won that you have the perfect starting XI," he said.

"We are focused on the last 16 because that is the match we need to win to progress, and so that means we need to see how to get the players in optimum condition for it."

Having been in New Zealand for the group phase, top spot would see Sweden head to Australia for a last-16 tie in Melbourne against the runners-up from Group E.

"It has been very convenient for the last three weeks, staying in the same place," said Eriksson, who recently joined Bayern Munich from Chelsea along with her partner, the Danish international Pernille Harder.

"It is now that the championship starts in earnest and it is part of the tournament, not being able to unpack your bag before you have to move on again.

"We have to stay flexible and take things as they come and make the best of it."