Parliament's 122 MPs will vote either to keep the purchase age at 18, split it to 18 for on-licences and 20 for off-licences, or raise it to 20.
The split-age plan is part of an alcohol law reform package the Government will introduce to Parliament before Christmas in a bid to curb binge-drinking.
An Otago Daily Times poll of the region's eight MPs showed three in favour, or leaning towards, retaining the status quo, two in favour of a split purchase age, one moving between the two options, and two undecided.
Waitaki MP Jacqui Dean did not want to express her opinion until she had a chance to hear the views of New Zealand.
"We have an awful long way to go before the vote is taken and in between now and then I'm hoping to talk to a lot of people about it," she said.
Different Bills introduced to Parliament would produce submissions on the matter which she would like to consider.
Dunedin list MP Michael Woodhouse also planned to survey his constituents before deciding on a stance.
"This is a conscience vote, which means not only my conscience but the views of the people of Dunedin and I will make my mind up closer to the end of the year."
However, he was "leaning towards" either the status quo, or a split purchase age because he was "pretty swayed" by the argument 18-year-olds were trusted with the responsibility of voting, marrying and going to war, so should be allowed to drink.
Dunedin South MP Clare Curran had not made a final decision yet but believed 18 was an "acceptable" age to legally purchase alcohol and a split purchase age would send "confusing messages to young people and the community".
She too wanted to hear the community's voice and intended to hold a public forum in Dunedin to discuss liquor issues generally.
She was also "seriously concerned the whole liquor debate has been hijacked" by the purchase age debate when alcohol problems spanned age, gender and socioeconomic groups.
Green co-leader Metiria Turei agreed, saying the purchase age was important, but had become a "political distraction from the more urgent need to reduce the drink driving limit to 0.5 and to severely restrict alcohol advertising".
She would vote to retain the purchase age of 18.
Te Tai Tonga electorate MP Rahui Katene thought having a split purchase age was "ridiculous" and also wanted it left as it was.
The alcohol debate made her "wild" because she believed the emphasis was being put on young people, rather than those who profited from the nation's binge-drinking culture.
Dunedin list MP David Parker was inclined to vote for a split purchase age, as was Dunedin North MP Pete Hodgson.
Mr Parker believed a change needed to occur, but it did not need to go as far as a flat purchase age of 20.
However, tightening up on the supply of alcohol to under-18s was more important than the debate on a purchase age, as was enforcement of not serving intoxicated patrons, he said.
Clutha Southland MP and deputy prime minister Bill English was "undecided".
