Beck (33), who is now based in Australia, won the inaugural event in terrible conditions last November, but faces an even bigger field this year.
Numbers across the marathon, half marathon and 10km run have swelled from 6000 a year ago to a maximum 9000, including 2000 in the 42.1km event.
Beck crossed the line in 2hr 55min 20sec last year to walk away with the $3000 winner's prize, and said she feels better prepared this time round.
''Training has gone really well. Awesome preparation, to be honest,'' she said.
''I feel stronger than last year and I'm looking forward to seeing what happens [today]. I really enjoyed it last year and again I am hoping to race in some cooler temperatures than in Aussie.
''The key is staying focused during the whole race. Everyone struggles towards the end and a couple of the bumps can test you.''
Beck has been coached by Sydney's David Byrne the past three months, who has got her running further as part of her training schedule.
She has not competed in that time, instead opting to focus solely on preparing for today's race.
However, she is sure to face a stiff rest from Dunedin's Mel Aitken.
Aitken crossed the line 4min 18sec behind Beck in second place last year, but is in considerably better form ahead of today's event.
The 38-year-old has had a stellar season, including a fifth place finish in the Auckland marathon, which doubled as the national championships, earlier this month.
Aitken clocked 2hr 55min 44sec in the race, which was won by Katie Kemp in 2hr 42min 35sec.
She finished second in a personal-best 2hr 49min 13sec in the Christchurch marathon in June, and won the Dunedin marathon in September.
Aitken also won the Wanaka and Hawaii half marathons, and national cross-country and road championship titles in the 35-plus section this year.
''I have had a really good season and am so looking forward to [today] on a course that I just love,'' she said.
''The mix of off and on road is great. The atmosphere was electric and the weather didn't faze me at all [last year].''
Napier's James Parsons is back to defend his men's title, after winning the race in 2hr 33min 41sec a year ago.
His biggest challenge could come from expat Japanese athlete Hirotaka Tanimoto, who now lives in Wellington.
Tanimoto won the Christchurch marathon in an impressive 2hr 24min 13sec in June, and along with Australian John Csongei and Sweden's Simon Karlsson, should push Parsons.
Former Dunedin runner Tony Payne, who is now a corporate lawyer in Auckland, will also line up in the race.
The two-time Dunedin marathon champion won the half marathon event in Dunedin in a personal-best 1hr 8min 25sec time in September, and also finished fifth in the Auckland half marathon in 1hr 11min 14sec earlier this month.
His personal-best over 42.1km is 2hr 24min 55sec, set in Rotterdam earlier this year.
This year's Dunedin marathon winner Romain Mirosa is also competing today and should feature in the top-10.
About 1300 runners from 39 countries have travelled to Queenstown for today's event, while more than 1500 are from Auckland.
Queenstown
Marathon
Start times: Children's run, 7.45am; 10km and half marathon, 8am; marathon, 8.45am.
Starts at Millbrook Resort, Arrowtown; finishes at Queenstown Memorial Centre
The numbers
Total field: 9000
Full marathon: 2000 (55% male, 45% female)
Half marathon: 5400 (65% female, 35% male)
10km: 1500 (76% female, 24% male)
Children's run: 100
