The Wellington Phoenix midfielder is known for his attacking runs down the flank but they have been largely absent during the All Whites' World Cup warm-up matches.

In the recent 3-1 loss to Slovenia he managed just three.

"It's taken a bit for me to adjust to that position," he conceded.

"Defensively, I haven't been doing too badly but my role is, more often than not, going forward and that's the aspect of the game that has been lacking recently.

"Maybe that has a little bit to do with opportunities but maybe I haven't been getting forward enough to help the rest of the team. Hopefully I can start doing that."

New Zealand have one last warm-up game against Chile before their World Cup opener against Slovakia on June 15.

The game against the South Americans tomorrow is purely a training exercise and will be played over three 30 minute periods.

New Zealand coach Ricki Herbert has already said he will use it to give his fringe players some game-time but he will also be acutely aware of making sure his first-choice line-up don't get injured just days out from one of the biggest days in New Zealand football's history.

But Bertos, who had to be carried off the field in the friendly against Australia following vicious challenges from Vince Grella and Tim Cahill, says if he is called on to play he will treat it just like any other game.

"You can't go into any game trying to avoid injury," he told the New Zealand Herald.

"If it happens, it happens. That's just luck. It's another tough game for us and a great way to finish off (our preparations)."

Preparations didn't go quite so smoothly at the team's first training session in South Africa.

The run out at their training venue in Daveytown, a township on the northern outskirts of Johannesburg, had to be cut short because of thick smoke caused by wood and coal fires burning as people tried to cook their evening meals and keep warm in the cooling temperatures.

The smog made it difficult to breathe and was so thick that the corner flags were barely visible and the players were restricted to a light jog.

Ahead of the clash against New Zealand, former Real Madrid and Chile striker Ivan Zamarano has echoed coach Marcelo Bielsa's warning that Group H rivals Honduras are not to be underestimated.

"The matches that Honduras have played in getting here mean nothing," he said.

"Marcelo Bielsa has tried to control the expectancy.

"We must keep our feet on the ground and remember that Chile are not among the favourites to win the World Cup."