Pugnacious lefthander Munro and Robbie O'Donnell put on 103 for the fourth wicket, before Munro found good support from allrounder Donovan Grobbelaar in a 79-run stand for the fifth.
Munro, who rarely faces more balls than he scores runs, completed his seventh first-class hundred in 98 balls when he was dismissed for 137 off 138 balls, including 10 fours and seven sixes. Legspinner Todd Astle and Ed Nuttall shared all five wickets.
The timing of Auckland's declaration today will be interesting.
They'll want to have Canterbury stretched to chase the target, but not so much that they shut the door on the idea and hunker down for a drawn result.
Wellington's game against Otago at Queenstown was called off at tea yesterday, going nowhere, with Wellington 255 for five in their second innings, leading by 301 overall.
Wellington veteran Michael Papps scored 110, his 26th first-class hundred in a lengthy career.
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