Steve Harmison looks set to play in England's opening warm-up match for the Test series with New Zealand after overcoming a back complaint.

The Durham fast bowler reported stiffness in his back yesterday, a problem he struggled with at the start of the tour to Sri Lanka before Christmas, but is in line to feature against a strong Invitational side in Dunedin tomorrow.

Chris Tremlett was retained from the defeated one-day side as cover for Harmison, who seemed to allay fears over his fitness when the Test squad assembled for the first time on tour today.

Harmison bowled at good pace for half an hour during a net session at the University Ground and will be assessed in the morning, but is expected to be fit enough to start a match where both sides will use 13 players to give maximum practice before the opening Test at Seddon Park on March 5.

"He's got a stiff back, but we don't think it's anything major and we think it's probably because of the flight," said coach Peter Moores.

"He's bowled for the last two days, including yesterday with it, but it seemed sensible to keep Tremlett on just in case anything more serious developed."

Hampshire fast bowler Tremlett, who did not make a competitive outing during the one-day leg of the tour, also seemed free of injury worries after undergoing a scan on a side strain.

The results gave him the all-clear although England have sent them back to their own ECB specialists to ensure they cannot detect anything serious which would require the call-up of another bowler as cover.

One-day captain Paul Collingwood and senior batsman Kevin Pietersen both missed today's training session and will be rested for tomorrow's two-day match prior to a further three-day warm-up match against Otago on Thursday.