Baan (19) won his first Otago senior men's title in Waikouaiti last month and will now look to add a senior title to the national men's under-20 title he won a year ago in Christchurch.
However, former Otago runner and 2014 champion Callan Moody, who now lives in Christchurch, stands firmly in his way.
Moody, who took up a job at the Canterbury District Health Board a few years ago, won the 12km race in 38min 50sec last year.
Last year's runner-up, Jonathan Jackson, of Auckland, is also competing in the 29-strong field, as is 2013 champion Malcolm Hicks, of Auckland.
Coached by four-time world cross-country representative Kerry Rodger, he is undefeated in cross-country competition this year.
Baxter (20) won the North Island title and Auckland championships earlier this season. His win in the Auckland championships included an impressive win over Hicks.
Otago runners Glen Chisholm, Lorenz Kissling, Kenneth McDonald and Jonah Smith are also competing for the senior title, which will be raced over six 2km laps of the course at Halswell Quarry Park.
This is Baan's first year competing in the senior ranks, and he only ran a cross-country event over 12km for the first time on his way to the Otago title last month.
Mel Aitken, who won her first Otago senior women's title last month, has entered the senior women's and masters women's 35-39 races today.
Aitken won the masters 35-39 race over 6km in 24min 48sec last year and will defend her national title at 11.45am. She will then have until 2.35pm before setting off in the 8km senior women's race.
Last year's winner, Camille Buscomb, of Waikato, is not back to defend her title. But Rachel Kingsford, who studied at the University of Otago before moving to Christchurch a few years ago, is set to compete.
She finished 13sec behind Buscomb in 29min 31sec a year ago, and will be chasing her first national title.
Otago has 38 runners, including impressive secondary school pupils Oli Chignell and Samantha Burke, competing across 10 races today.
