Broad finished with six for 51 as England bowled the Kiwis out for 254 and were therefore able to enforce the follow-on, despite half-centuries from the prolific Brendon McCullum (69) and BJ Watling (60). Even after that pair's century stand for the sixth wicket, New Zealand still could not quite eke out enough runs to escape the follow-on.
They fared much better, on the way to 77 for one, second time round. Broad, however, is confident he and his fellow bowlers have found the key to prosper on a wicket which still favours bat. He said: "I'm delighted to have picked up 'five-for' in a Test match, but more importantly to have bowled New Zealand out to be able to enforce the follow-on - and I hope we'll get some early wickets tomorrow."
England had no option but to put their hosts back in again, with the remnants of Cyclone Sandra set to hit Wellington late on Sunday before a deluge on Monday.
"With the weather around, it was important to be able to enforce that," said Broad. "It's not often enforced, because the bowlers tend to like a bit of a rest, and it's good to get their batsmen back out in the field and build a big lead with scoreboard pressure.
"But with the (weather) radar around, it's really unsure how much cricket will be left in the next two days. That was the only reason behind it.
"It will be a 'reset' tomorrow, build patience because it's still a very good batting wicket. There's not a lot there, especially for the seamers."
Broad's pace colleague James Anderson spent a short time off the field in the final session on Saturday, with a stiff back.
But he was still able to get through his share of overs, and England are optimistic he will be fine on Sunday.
Broad said: "I think he's okay. He's just torn into that wind for 20 overs and it's taken it out of him a little bit. This wind, howling through, can stiffen the body up quite badly. So it's about keeping mobile."