About 140 participants from around New Zealand took part in the event, which saw military personnel, in teams and as individuals, tackling the 26km course over Flagstaff and Swampy Summit on Saturday.
The troops wore military fatigues and webbing and carried assault rifles and backpacks full of gear weighing up to 20kg while tackling the course.
And the strain was showing for at least one team spotted by the Otago Daily Times, who stopped at a checkpoint to scoff jellybeans, then waited for one member to finish vomiting before pushing on again.
Captain John Aitken, of 2/4 Battalion RNZIR (formerly 4 Otago Southland Battalion Group), said recent rain had created muddy and challenging conditions. At least one participant was forced to withdraw mid-race due to ''illness'', after reaching one of the summits, he said.
''With the recent rain, the tracks are quite wet underfoot.''
Members of Defence Health Team 1, a combined group of Army, Navy and Air Force trainee medics from Burnham military base, near Christchurch, won the team award and the Battle Tab Trophy in a time of 3 hours 55 minutes.
Capt Aitken, of Dunedin, said the event was first held in 2002 as a test of physical fitness for Dunedin's rifle companies.
Its popularity had since attracted territorial and regular force soldiers from around the country, he said.
