Ben Stokes has been "frustrated" by his back injury in New Zealand but has also been heartened by the pace he has been able to achieve off a shortened run-up.

Stokes picked up a back problem during the one-day series, which was his return to international cricket after missing the Ashes and one-day series in Australia, and was unable to bowl in the first Test at Eden Park. In Christchurch he sent down six overs in New Zealand's first innings and is hopeful he will be back towards full tilt in a couple of weeks.

"It's been frustrating. I had a few injections into an injury I had when I was a kid," Stokes told Test Match Special. "At the same time it's getting slowly better. It's a patience game, a day-to-day thing. Hopefully in a week or two times it will be good to go."

Stokes has been working with Chris Silverwood, England's bowling coach, on trying and get his delivery stride into a straighter line to ease the pressure on his back.

"I'm working alignment…it's more a long-term plan," he said. "I think if I can cancel out my dip-in, which obviously loads my lower back where I've had the pain recently, that will do me good in the future

"When I was looking at my paces off that [short run-up] I was bowling as fast as I normally do. I don't think I'll resort to that short of a run-up but it proves to me that I don't need to over-try. Sometimes I've been guilty of that."

Stokes most significant performance so far in the two Tests was his second-innings 66 in Auckland which gave England hope of saving the game before he fell to ill-judged hack at Neil Wagner in the over before dinner. Stokes batted at No. 5 in that match, a position coach Trevor Bayliss sees as a long-term option, though he was back to No. 6 in Christchurch.

"I won't look back on the dismissal with too much pleasure but I had time at the crease which was a pleasing thing," he said. "Going forward it's a template I can use, I have the game to push games on but also the patience to survive."

Stokes will head to the IPL at the conclusion of the New Zealand tour to join Rajasthan Royals before returning to England ahead of the Test series against Pakistan which starts on May 24.