Kane Williamson and BJ Watling produced a world record sixth wicket partnership of 365 runs to guide New Zealand to 524 for five before captain Brendon McCullum declared their second innings closed after tea on the fourth day of the second test.
Sri Lanka need to score 390 in 107 overs at the Basin Reserve to win and tie the two-match series after New Zealand won the first game by eight wickets in Christchurch.
Williamson scored 242 not out, his first test double century, while Watling made 142 not out, his fourth test ton, after the pair had been thrust together after lunch on day three with New Zealand on 159 for five, a lead of just 24 runs.
Their record partnership surpassed the 352 Watling and McCullum scored against India last year, also at the Basin Reserve, where Watling made his previous best test score of 124.
