A back problem has ruled New Zealand all-rounder Jacob Oram out of the second and final Test against Bangladesh.

The all-rounder suffered pain in his lower back late on day three of the first Test in Chittagong and did not bowl again, although he was at the crease as New Zealand completed their three-wicket win to take a 1-0 lead in the series.

Scans have revealed a disc problem but there are also other areas around the bone which are of concern and require further diagnosis.

The 30-year-old, who has a history of back ailments, will remain with the side for the first day's play in Mirpur on Saturday before returning home for further examination.

"There is a disc problem which is no doubt causing him discomfort but there are some other areas around the bone which we're not too sure about and it's a bit hard to get the proper diagnosis here," Black Caps manager Lindsay Crocker said.

"The best thing for him to do is to get home to see a specialist there who can compare his history with what we've seen now and then have a better idea as to what we're dealing with."

Crocker revealed Oram, who is the number one all-rounder on the International Cricket Council's rankings, was frustrated by his latest setback which follows hip and hamstring injuries that sidelined him during the home and away series with England.

"He's disappointed that he can't contribute in the way that he would like to do. He's also frustrated by the fact that it has happened to him again," Crocker told Radio Sport.

"He feels he's let everybody down, which is not what everyone else if feeling about it of course.

"We're disappointed he can't stay involved. He's an integral member of our side given that he is one of our front line bowlers and bats very effectively too.

"There's bitter disappointment all round really."

Oram was a key figure in the Black Caps' 2-1 one-day series win against Bangladesh and played a significant role in applying the screws to the hosts' first innings in Chittagong where he allowed just 14 runs off 20 overs, 14 of which were maidens. In the second innings he took none for 19 off eight.

With two Tests next month against Australia and tours by the West Indies and India later in the season, New Zealand's cautious approach is understandable.

"We need to get him home to just see what we're dealing with. It's too early to speculate on when he will be able to make a return.

"We need to get him home and get him properly diagnosed and then treated because we've got a big campaign ahead of us."

All-rounder Grant Elliott, who replaced Oram for a Test against England in March, is the likely replacement but Mark Gillespie could also come into the mix depending on the wicket at the Shere Bangla National Stadium.

Bangladesh enter the match still seeking their first Test win but after pushing the Black Caps hard in Chittagong coach Jamie Siddons is hopeful.

"The more we keep presenting ourselves in the one-dayers and the more we keep giving ourselves chances, we'll learn how to win. That'll make me and everyone happy," he told the Bangladesh Cricket official website.

"At home we catch people by surprise with our wicket and we bowl very well on it.

"We bowl well, get wickets and the opposition learn their lessons just like South Africa did last time and improved in Chittagong.

"New Zealand will play a bit different in Dhaka but it's a different wicket so hopefully we can catch them on the hop."