Dickey and Reardon will need to respect another contender who was a three-peat national champion from 2016-18 in Taupo's Brad Groombridge, again among the favourites this time around.
Manawatu's former national cross-country champion Paul Whibley is another expected to challenge for the senior title this year, along with the always-fast Brandon Givens, from Raglan.
Rotorua's Ethan Harris, Hamilton's Andrew Charleston and Phillip Goodwright, Te Kauwhata's Jacob Brown, Pukekawa's Jim Orton, Toko's Karl Roberts and Napier's Mackenzie Wiig could also be battling near the front.
"We have had two former national cross-country champions [Awakino's Adrian Smith and Marton's Cam Smith, no relation] marking out the track for us, so it should be an excellent course," said Motorcycling NZ cross-country commissioner Chris Smyth.
"It might be a little dry and dusty if we don't get rain before the weekend, but it should be an excellent test for the riders.
"There is a wide variety of terrain they will cover...from open farmland, to tight native bush sections, gorse and pine trees – a bit of everything, really.
"We have a new non-championship class this year too – the Yamaha Cup class for riders aged between 15 and 19 years.
"This is a development class. This is where the riders of the future may come from," he said.
The 90-minute junior race kicks off at about 9am on Sunday, with the three-hour senior race to follow at about 11.30am.
The New Zealand Cross-country Championships series is supported by Yamaha NZ, O'Neal apparel, The Dirt Guide, Oakley goggles, Bel Ray oils and Michelin tyres.
Calender
2020 NZ Cross-country Champs
Round 1: Sunday, February 16, Bush Riders MCC, Marton; Round 2: Sunday, March 22, Central Hawke's Bay MCC, Flemington; Round 3: Sunday, April 26, Marlborough MCC, Nelson; Round 4, Saturday, May 23, Taupo MCC, Taupo.