England have called up young fast bowler Stuart Broad for the tri-series finals against hosts Australia.

Seamers Jon Lewis and Chris Tremlett have been released from the squad due to injuries and will return home. Lewis has an Achilles problem and Tremlett a bad back.

Broad, 20, played five home one-day internationals against Pakistan last year. He is the son of former England opening batsman Chris Broad.

England beat New Zealand by 14 runs on Tuesday in Brisbane to reach the best-of-three finals which start in Melbourne on Friday, and coach Duncan Fletcher said the team had benefited from the return of captain Michael Vaughan after injury.

"He's captaining England successfully, which is very, very important," Fletcher told reporters on Wednesday. "If you've got a few wins under your belt you normally get confidence from that. You believe in your ability and he's a very important factor for us."

Vaughan is still struggling to completely shake off the hamstring injury which forced him out of five tri-series matches.

"You always worry with Michael because that experience is immense," Fletcher said, adding that all-rounder Andrew Flintoff was enjoying playing without the burden of the captaincy which he shouldered during the Ashes series.

"We feel when he's not captain he feels a little bit freer and his batting -- especially his bowling -- is a lot more confident and there's a weight off his shoulders," Fletcher said.

"He seems a lot more relaxed. Anyone who's not captain of the side would be a little bit more relaxed."