Off-spinner Agha Salman and pacer Naseem Shah helped Pakistan derail New Zealand to 309-6 Monday after opener Devon Conway scored a brilliant hundred on the first day in the second Test in Karachi.

Salman grabbed 3-55 and Naseem took 2-44 to trigger a New Zealand middle order slump which saw the tourists lose five wickets for 45 runs during the final session, slumping from 234-1 to 279-6.

At close, Tom Blundell and Ish Sodhi were batting on 30 and 11 respectively as they try to revive New Zealand's innings.

Conway, who scored 122, put on 134 for the opening wicket with Tom Latham (71) after New Zealand won the toss on a National Stadium pitch that had traces of grass but did not initially support bowlers.

Conway steadied the innings with another 100-run stand for the second wicket with Kane Williamson who made 36, but Pakistan pulled back after the visitors were 226-1 at tea.

Salman had Conway caught behind by Sarfaraz Ahmed soon after tea to make it 2-234 before six runs later Naseem dismissed Williamson in the same manner.

Conway struck 16 boundaries and a six in his 257-minute stay at the crease.

Salman then struck twice, beating Daryl Mitchell's defence for three and had Henry Nicholls caught behind with a turning delivery for 26.

Abrar Ahmed took his only wicket by trapping Michael Bracewell for nought.

The two-match series is tied at 0-0 after the first Test -- also in Karachi -- ended in a tame draw.

In the morning, Pakistan's three-pronged pace attack looked helpless until Naseem struck in the sixth over after lunch, trapping Latham leg-before with a sharp incoming delivery.

Latham, who scored 113 in the first match, hit nine boundaries in his 100-ball knock, his 24th Test half-century.

Conway was lucky to survive a sharp chance when Saud Shakeel failed to hold on to a miscued drive off Hasan Ali on 89.

Pakistan brought on Abrar Ahmed in the ninth over, but there was no sign of turn as Conway smashed a boundary and a six off the spinner's second over.

The hosts picked Naseem and Hasan in place of spinner Nauman Ali and fast-bowler Mohammad Wasim after the first Test, while New Zealand picked pacer Matt Henry over Neil Wagner.