NEW ZEALAND head coach Rob Walter remains wary of Jos Buttler despite the England opener’s wretched form at the T20 World Cup.

Buttler is widely regarded as England’s greatest white-ball batter of all time, a menacing presence at the top of the order in T20s and one of only four batters to go past 4,000 runs in the sprint format.

However, the double World Cup winner has amassed just 62 runs in six innings in India and Sri Lanka and alarmingly failed to reach double figures in each of his last four visits to the crease.

England white-ball captain Harry Brook has leapt to the defence of his predecessor, urging everyone to “cut him a little bit of slack,” confident it is a matter of when not if Buttler rediscovers form.

And Walter was adamant he will not be underestimating the big-hitting 35-year-old as New Zealand and England vie to finish top of their Super 8 group at Colombo’s R Premadasa Stadium on Friday.

“I don’t think you’d ever doubt the quality of Jos Buttler,” Walter said. “He’s got enough numbers behind his name to suggest that he’s one of England’s best white-ball batters.

“But we know that all batters probably find a space in their career somewhere where there’s a lull and sometimes it only takes one knock for that to change.

“Hopefully that’s not tomorrow, by the way, but no one will ever doubt his quality and so we won’t.”

While Buttler, who has gone 16 international innings without a fifty this winter, has appeared out of sorts, Brook guaranteed England’s semi-final spot with a barnstorming 50-ball hundred against Pakistan.

New Zealand knocking out tournament co-hosts Sri Lanka has gone a long way to making sure they reach the knockout stages but they need to avoid defeat against England to make absolutely certain.

Figuring out a way to stop Brook could be crucial, with the Yorkshireman averaging nearly 52 in all formats against the Black Caps, as well as a staggering strike rate of 173.28 in seven T20s.

Brook promoted himself to number three against Pakistan in Pallekele on Tuesday and could stay there for the rest of the tournament but Walter dismissed the view it is a significant factor for the Kiwis.

“There’s no doubt he’s a wonderful player,” Walter added. “When in the order he comes in, it’s probably irrelevant — we’ve got to bowl to him whether it’s in the first over or the 15th over.

“Batting orders can be overstated at times, and I think whatever decision they make we’ll be ready for.”