Joyce will bat at four against New Zealand on Tuesday after Pietersen went home with a fractured rib.

"I'm not going to try to be KP. I can't do that -- very few people can," said Joyce, who has just three ODI caps.

"I'm not as experienced as he is either so I've got to try and grow up pretty quickly and get runs for the team."

Chairman of selectors David Graveney backed Joyce, who has been used as an opener before, to make his mark batting behind Andrew Strauss, Michael Vaughan and Ian Bell.

"It will be great for him to show what he can do because I believe he's a very talented player who has a huge future," said Graveney of Joyce.

"We're happy at the present stage with the order, with Michael coming back and showing good form, together with Strauss and Bell.

"That's how we would like to line up the top order so we will run with that."

England's approach is at odds with most other international sides, who put big-hitting batsmen at the top of the order in one-day games to take advantage of fielding regulations.

Irishman Joyce, who qualified for England a year ago, has been with the squad in Australia since Marcus Trescothick returned home in November.

But the only international action he has seen so far was in last week's Twenty20 international, when he was dismissed third ball.

Graveney told BBC Radio Five Live he is completely confident Pietersen will recover from a broken rib by the time England's World Cup squad is cut to 15 in mid February.

"It is a massive blow -- he's been the form player for the period we've been here," he said of Pietersen.

"Fortunately by the time we announce the 15 he should have made a full and speedy recovery."

Essex batsman Ravi Bopara has been added to the squad, gaining the nod over more experienced rivals because of his time in Perth with the England Academy before Christmas

He will join the touring party in Brisbane in time for Friday's day-night match against Australia.

"Kevin Pietersen was a middle order batsman and Ed slots in there and we think Ravi is the right person to cover (all) the batting positions," Graveney added.

"It will be fantastic for (Bopara) to be part of the senior squad and to understand what is required to achieve at the highest level."