New Zealand captain Kane Williamson, who suffered a hamstring injury in the second Twenty20 against Pakistan, is unlikely to take any further part in the series, coach Gary Stead said Monday.

Williamson was already set to miss the third game on Wednesday, and with the first Test against South Africa less than three weeks away, Stead said his star batsman would probably sit out the final two games as well.

"With the test matches so close as well and in the big scheme of things (they are) a higher priority I think we'll try and make sure he's right for that," Stead said.

New Zealand lead the five-match series 2-0, with Williamson contributing 26 off 15 before retiring hurt in Sunday's second encounter, in which his side won by 21 runs.

Tim Seifert is expected to replace Williamson in the batting line, with Stead indicating Seifert was already set to replace Devon Conway as wicketkeeper at some stage in the series.