A Herald poll of all 121 MPs found that keeping the status quo of a purchase age of 18 was the most favoured option. Thirty MPs wanted the purchase age to remain at 18, 27 MPs wanted it raised to 20 in all places, and 22 wanted a split purchase age.
Of those who were undecided, 10 were considering a split vote and several others have previously indicated they preferred the split option.
The outcome could depend on the order the options are voted on, which has not yet been decided by Ms Collins. Parliament must discuss which purchase age should be voted on first so that other voting options are not given an advantage.
The poll shows the current Parliament is more fractured over the drinking age than the previous one.
In 2010, a Herald survey showed more support for the split option and far less support for raising the purchase age to 20 in pubs as well as off-licences.
When the changes were first tabled, 31 MPs favoured the split age, 18 MPs wanted to keep the age at 18, and 12 MPs wanted only 20-year-olds to be able to drink in pubs and buy alcohol at off-licences.
The contrast is partly due to the arrival of New Zealand First in Parliament, because all but one of its members was keen to see the purchase age raised to 20 across the board. The Greens also have a stronger presence in Wellington, and 13 of the party's 14 MPs said they would keep the age limit at 18.
Many MPs stressed the purchase age could not be considered in isolation from the rest of the reforms proposed by the bill.
Labour MP Lianne Dalziel said the Government's reforms had focused too narrowly on age at the expense of the price of alcohol, availability and marketing.
"Until the Government has the courage to deal with those three issues the age is irrelevant."
MPs from poorer electorates were most likely to vote to raise the age to 20.
Mangere MP Su'a William Sio said his electorate had urged him to lift the drinking age.
National MP Simon Bridges said he was still undecided but would probably choose to raise the limit across the board. He felt the 14- to 17-year-olds had greater access to alcohol from their 18-year-old peers.
The Alcohol Reform Bill's package of changes also includes tightening consent rules for adults who supply alcohol to minors and making itharder for venues to gain a liquor licence.
HOW YOUR MPS MIGHT VOTE:
31 MPs
To keep the alcohol purchase age at 18.
27 MPs
To raise the age to 20.
22 MPs
To split the drinking age (18 for bars, 20 for off-licenses).
20 MPs
Undecided.
17 MPs
Undecided but leaning towards a choice.
5 MPs
Won't say.
18 FOR BOTH ON AND OFF LICENSE
Browning, Steffan - Greens List
Clendon, David - Greens List
Delahunty, Catherine - Greens List
Genter, Julie Anne - Greens List
Hague, Kevin - Greens List
Hughes, Gareth - Greens List
Logie, Jan - Greens List
Mathers, Mojo - Greens List
Norman, Russel - Greens List
Turei, Metiria - Greens List
Roche, Denise - Greens List
Sage, Eugenie - Greens List
Walker, Holly - Greens List
Ardern, Jacinda - Labour List
Chauvel, Charles - Labour List
Curran, Clare - Labour Dunedin South
Fenton, Darien - Labour List (previously said split)
Hipkins, Chris - Labour Rimutaka
Robertson, Grant - Labour Wellington Central
Henare, Tau - National List
Lee, Melissa - National List
Mackey, Moana - Labour List
Mallard, Trevor - Labour Hutt South
Robertson, Grant - Labour Wellington Central
Woods, Megan - Labour Wigram
Dean, Jacqui - National Waitaki
Kaye, Nikki - National Auckland Central
O'Connor, Simon - National Tamaki
Ross, Jami-Lee - National Botany
Williamson, Maurice - National Pakuranga
Dunne, Peter - United Future Ohariu
SPLIT - 18 FOR ON LICENSE AND 20 FOR OFF LICENSE
Dalziel, Lianne - Labour Christchurch East
Dyson, Ruth - Labour Port Hills
Goff, Phil - Labour Mt Roskill
Huo, Raymond - Labour List
Lees-Galloway, Iain - Labour Palmerston North
Little, Andrew - Labour List
O'Connor, Damien, Labour West Coast-Tasman
Parker, David - Labour List
Prasad, Rajen - Labour List
Shearer, David - Labour Mt Albert
Street, Maryann - Labour List
Twyford, Phil - Labour Te Atatu
Adams, Amy - National Selwyn
Coleman, Jonathan - National Northcote
Collins, Judith - National Papakura
Goodhew, Jo - National Rangitata
Groser, Tim - National List
Guy, Nathan - National Otaki
Key, John - National Helensville
Tremain, Chris - National Napier
Smith, Nick - National Nelson
Andrew Williams - New Zealand First List
20 YEARS OLD FOR BOTH ON AND OFF LICENSE
Clark, David - Labour Dunedin North
Cosgrove, Clayton - Labour List
King, Annette - Labour Rongotai
Moroney, Sue - Labour List
Sio, Su'a William - Labour Mangere
Flavell, Te Ururoa - Maori Waiariki
Sharples, Pita - Maori Tamaki Makaurau
Turia, Tariana - Maori Te Tai Hauauru
Blue, Jackie - National List
Calder, Cam - National List
Foss, Craig - National Tukituki
Lotu-Iiga, Sam - National Maungakiekie
Macindoe, Tim - National Hamilton West
Parata, Hekia - National List
Roy, Eric - National Invercargill
Ryall, Tony - National Bay of Plenty
Sabin, Mike - National Northland
Shanks, Katrina - National List
Tolley, Anne - National East Coast
Upston, Louise - National Taupo
Horan, Brendan - New Zealand First List
Lole-Taylor, Asenati - New Zealand First List
Martin, Tracey - New Zealand First
O'Rourke, Denis - New Zealand First List
Peters, Winston - New Zealand First List
Prosser, Richard - New Zealand First List
Stewart, Barbara - New Zealand First List
UNDECIDED
Banks, John - Act Epsom
Faafoi, Kris - Labour Mana
Titikatene, Rino - Labour Te Tai Tonga
Ardern, Shane - National Taranaki-King Country
Bakshi, Kanwaljit Singh - National List (previously said split)
Barry, Maggie - National North Shore
Bennett, Paula - National Waitakere
Brownlee, Gerry - National Ilam (previously said split)
English, Bill - National Clutha-Southland
Finlayson, Chris - National List (previously said split)
Goldsmith, Paul - National List
Harawira, Hone - Mana Te Tai Tokerau (previously said 18)
Hayes, John - National Wairarapa
Joyce, Steven - National List
McKelvie, Ian - National Rangitikei
Mitchell, Mark - National Rodney
Ngaro, Alfred - National List
Simpson, Scott - National Coromandel
Wagner, Nicky - National Christchurch Central (previously said split)
Yang, Jian - National List
UNDECIDED BUT LEANING TOWARDS A DECISION
Graham, Kennedy (split) - Greens List
Cunliffe, David (20 or split) - Labour New Lynn
Jones, Shane (20) - Labour List
Mahuta, Nanaia (18 or 20) - Labour Hauraki-Waikato
Robertson, Ross (20) - Labour Manukau-East
Wall, Louisa (split or 20) - Labour Manurewa
Auchinvole, Chris (18) - National List
Bennett, David (18) - National Hamilton East
Borrows, Chester (split or 20) - National Whanganui
Bridges, Simon (20) - National Tauranga
Carter, David (18 or split) - National List
Heatley, Phil (split) - National Whangarei
Hutchison, Paul (18 or split) - National Hunua
McClay, Todd (split) - National Rotorua
Smith, Lockwood (18) - National List
Woodhouse, Michael (split or 18) - National List
Young, Jonathan (split) - National New Plymouth
WON'T SAY/NO REPLY
Horomia, Parekura - Labour Rawhiti
King, Colin - National Kaikoura
McCully, Murray - National East Coast Bays
Tisch, Lindsay - National Waikato
Wilkinson, Kate - National Waimakariri
