Why? To ''scare off'' the many Aucklanders who have travelled to Dunedin to compete in the event at the Gladfield Golf Club.
Chignell, of John McGlashan College, and Murphy, of Kavanagh College, are two of 124 Otago runners competing in the event, which has attracted 829 runners from 112 schools across the country.
Chignell and Murphy will compete in the senior boys (6km) and senior girls (4km) races respectively, races they both won on the same course at the Otago secondary school championships last week.
Chignell clocked 21min 24sec last week, but believes he needs to be at least half a minute quicker to accomplish his goal of finishing in the top 12 and making a New Zealand team to compete in Australia later in the year.
With 216 competitors, the senior boys field is the largest of the seven races today, and is stacked with talented runners.
Daniel Hoy, of Westlake Boys' High School, finished second a year ago and is sure to push for the top spot on the podium, while national junior steeplechase champion Jack Beaumont, of Central Southland College, is another to watch.
''There's quite a few really fast guys,'' Chignell said.
''There's quite a few guys from up north who are all top-notch athletes. But it's hard to tell over 6km, because most of those guys are 1500m or 3km runners.
''I'm more of a long-distance runner ... I've been doing a lot more longer stuff over winter.''
Chignell, one of 32 Otago runners in the senior boys race, last competed in the national event two years ago, finishing 18th in the junior race.
However, he took a tumble after being tripped up on the first bend, and had to work his way back from 90th place.
Chignell enjoyed testing the course out last week, and rates it as one of his favourites with ''lots of wide corners''.
Despite the tough field, Chignell believes finishing in the top 12 is ''doable''.
Murphy, one of 17 Otago runners in the 128-strong senior girls field, will also be up against a stack of talented runners.
Kelsey Forman, of Wellington East Girls' College, who will compete in the steeplechase at the world youth championships in Colombia next month, is the favourite.
Last year's third-placed runner, Isabella Richards, of St Kentigern College, is also back for another crack.
Murphy, a member of the senior women's 4x1500m Hill City-University team which won the Lovelock Relay last month, won the Otago senior girls title in just under 17 minutes last week and described the course as ''good but tough''.
She had been busy training for today's race, and is hopeful she can push the best secondary school runners in the country.
''It would be really great to get in the top 10. That would be really good, but I'm not quite sure where I'm at at the moment.''
Sammy Burke, of Mt Aspiring College, won the Otago under-16 girls title last week, and will also compete in the senior girls section today.
At the end of the day, selectors will name a team of 24 - 12 boys and 12 girls - to compete in the world secondary schools championships in Hungary next year.
NZ schools cross-country
Gladfield Golf Club, today
10am: Combined para girls and boys (2km)
10.30am: Year 9 girls (3km)
11am: Year 9 boys (3km)
11.30am: Junior girls (3km)
Noon: Junior boys (4km)
12.30pm: Senior girls (4km)
1pm: Senior boys (6km)
