Elliott has not trained fully with the All Whites squad this week because of a hip injury and will have to get through the team's final training session at Westpac Stadium tonight to be in selection contention.

"It's a time factor for Simon. We need to make the right call and we're prepared to give it the right amount of time as well," Herbert said.

"He desperately wants to be part of it as you would expect. We're giving him every opportunity we can."

If Elliott is ruled out former Scottish youth international Michael McGlinchey, who was impressive coming off the bench for the final 20 minutes of the 0-0 draw in the first leg of the play-off in Manama, is likely to take his place in midfield.

The buzz surrounding what is the biggest football game in recent times in New Zealand has grown steadily in Wellington since the team assembled at the start of the week.

But Herbert believes the players have coped well with the pre-match hype and will go into the contest in a confident frame of mind.

"I've liked what I've seen. There is a very good spring in everyone's step. There's been a very positive approach to everything we've done.

"As the clock runs down why wouldn't there be a bit of pressure and tension and excitement around it?

"It's a wonderful opportunity for the game. They will handle it definitely."

Away goals count double in the tie with Herbert irritated by the fact the visitors will get 120 minutes - including extra-time - to take what could be a decisive advantage if the second leg also finishes goalless.

"I find it quite unique that you get 120 minutes to get yourself an advantage of the away goal. We only had 90 minutes when we were away," the coach said.

"But that's the lie of the land. I've no reason to think the tie won't be tight. I think it was very competitive when we were over there.

"They are a technically good side. They've got pace. I think they will keep coming and I think that's been evident in their away fixtures.

"In some cases you could argue they have been the better team away from home.

"We're under no illusion as to what the task is going to be tomorrow night. But where we sit and what we've done during the week we also feel confident."

Bahrain only arrived in the New Zealand capital yesterday after choosing to prepare earlier in the week in Sydney.

The decision to do that raised a few eyebrows given the nature of Wellington's climate compared to that across the Tasman but coach Milan Macala seemed unfazed despite a chilly first training session.

"It's good weather for football. Because it's colder I hope that our players will run more," he joked.

There is plenty at stake for both teams tomorrow. It is 27 years since New Zealand last featured at a World Cup, while Bahrain have never qualified for football's greatest tournament after losing out to Trinidad & Tobago in a play-off in 2005.

"This game is an opportunity for both countries. I think it will be a very tough game," said Macala.

"For both countries it's a fantastic opportunity because now we are at the same level as Russia, Greece, Slovenia, Ukraine, Bosnia-Herzegovina, Portugal, France and the Republic of Ireland (who are all playing off for places in next year's tournament in South Africa).

"This is very, very important. We have this opportunity to represent our country.

"But because you played in 1982 in Spain I hope you give us a chance to play this time in South Africa," the Czech coach added with a smile.