New Zealand head coach Danny Hay has urged his players to "seize the moment" by producing an upset against Costa Rica to claim the last remaining World Cup finals spot.

The two sides face off at Ahmad bin Ali Stadium on Tuesday for the right to return to Qatar later this year and join Germany, Japan and Spain in Group E.

A total of 31 countries have qualified for the global showpiece following Australia's penalty shoot-out win against Peru on Monday, leaving one place up for grabs.

New Zealand enter the intercontinental play-off clash as underdogs as they sit 101st in the latest FIFA rankings, 70 places below their Central American opponents.

The All Whites cruised through the extended qualifying process, racking up 5-0 and 7-1 wins along the way, but now face undoubtedly their toughest test yet in Costa Rica.

Whereas New Zealand have only ever qualified for two World Cups, and none since 2010, Costa Rica have qualified five times and are seeking a third straight finals appearance.

Hay's side are in a relaxed mood, though, with the 47-year-old glad that all the pressure is on the opposition.

"The world's media have basically written us off, given us no chance," Hay said at his pre-match news conference. "They're 31 in the world playing against 101 in the world. 

"I'm sleeping pretty well. I'm not sure their coach will be, though.

"We've got a great group. They're injury-free, they’re in a good space mentally, that’s why we need to seize the moment now. This really is our moment, this is our time."

New Zealand have been boosted by the return to fitness of captain Winston Reid, who had been struggling with a groin injury.

They have warmed up for Tuesday's match with a 1-0 defeat to Peru and goalless draw against Oman, both of those games being friendlies.

Costa Rica have lost just one of their past nine matches, meanwhile, but head coach Luis Fernandez Suarez is not taking New Zealand for granted.

"We'll make sure that the group is strong mentally," he said. "New Zealand are a team that like to make things dangerous. 

"They are a team that from the back with their goalkeeper almost always playing inside, from the beginning to the last third, with one of their advantages being aerial football.

"But for every situation or attack New Zealand present, we have prepared something to respond to it."