Thorburn and Bevan Stevens (Caversham) have been the stand-out runners in Otago this winter and should be able to challenge for places in the top six and lead Otago to the podium in the teams race over the 12km course.
Thorburn (28) displayed his temperament when he beat Stevens in the Otago championships on the Waikouaiti course last month.
Stevens caused a major upset when he beat Thorburn in the Edmond Cup, but he was not able to repeat the performance in the Otago cross-country.
Thorburn is a converted duathlete and has represented New Zealand at world mountain running championships.
Stevens has had a disappointing few years since winning the New Zealand junior steeplechase title in 2005.
He surprised the pundits when he won the Edmond Cup in June and came second to Thorburn at the Otago cross-country.
Canterbury's Phil Costley (40), the winner of 30 national titles, has won the senior men's cross-country six times.
He will go head to head with Melbourne-based Shaun Krawitz and Alex Parlane (Auckland).
Costley first won the cross-country crown in 1997 and his last win was in 2006.
Krawitz won the cross-country trial for the world championships in Trentham in January and went on to represent New Zealand in Poland where he finished 98th. Krawitz also competed at the 2004 world junior cross-country championships where he finished 88th.
First year senior Parlane won the North Island championships in Taupo by nearly a minute.
He has been clearing out at the half way point in his races and maintaining commanding leads to the finish.
Others expected to vie for the top six are Stephen Lett (Auckland), the MacDonald twins Iain and Kyle (Waikato-Bay of Plenty), Hamish Carson, Terefe Ejigu, Stefan Smith and James Coubrough (Wellington), Luke Hurring and Brett Tingay (Canterbury).
The other Otago runners in the event are Caversham's Daniel Balchin, Lyndon Brown, Tony Payne and Leith's Andrew Lonie and Jason Palmer.
Fiona Crombie (Canterbury) will be defending the senior women's title over 8km.
The next three place getters from last year are back - Kellie Palmer (Canterbury), Sarah Biss (Waikato-Bay of Plenty) and Rachel Kingsford (Otago).
Also in with a chance are Tina Harris (Wellington) and Barbara Roy (Otago).
Following his national record breaking 10,000m run at the world junior track and field championships in Canada, Aaron Pulford (Waikato-Bay of Plenty) should retain his junior men's 19 title over 8km.
The Otago runner in the field is Alex Gorrie (Hill City).
Anna Kean (Ariki) is competing in the girls aged 16 event.
