Bay of Plenty riders are set to do battle when the New Zealand Cross-country Championships kick-start into action this weekend.

The four-round series gets underway in the Waikato region on Sunday, February 21, although many of the leading contenders have already lit the fuse on what many expect will be another season of motorcycling fireworks in 2016.

Taupo's Brad Groombridge (Suzuki), expected to be a leading contender this season. Photo: Andy McGechan, BikesportNZ.com.

What would be considered 'warm-up' events have certainly given a good indication that the competition will be fierce in the nationals this season.

Rotorua's Scotty Birch riding his Honda is expected to challenge Mokau's four-time former national No.1 Adrian Smith (Yamaha) who is certainly among the favoured few to win the nationals again this year.

Riders such as Morrinsville's Tesselaar brothers, Nathan and Hayden, Palmerston North's former national champion Adam Reeves, Pahiatua's Charles Alabaster, Masterton's Allan Gannon, Maruia's Ethan Bruce, Aucklanders Chris Power and Sam Greenslade, Pukekawa's Anthony Parker and Morrinsville's Simon Lansdaal could also threaten.

However, there could be surprises in store for the cross-country regulars in the form of men from other, parallel, bike codes – riders such as Taupo motocross ace Brad Groombridge and Howick enduro gun Liam Draper, along with South Island enduro exponents Angus, Hamish and Mitchell Macdonald, from Christchurch.

Brad and Liam teamed up to win the Cambridge Four-Hour Cross-country Race last weekend and, with no clash of dates between the cross-country, motocross and enduro codes this season, it's likely these men will be a feature of cross-country race action in 2016.

Among the young guns to watch out for will be Palmerston North's James Galpin and Wairoa's former national junior champion Reece Lister, both of whom have been strong in recent events.

Sunday's venue for round one is at Findlay Road, signposted from Red Fox Tavern, State Highway 2, Maramarua, just up the road from Huntly.

"The course on Sunday features a bit of everything," Motorcycling New Zealand cross-country commissioner Chris Smyth says.

"The national's venues are spread equally over the North and South Islands and there has been a tremendous amount of interest being shown by the riders. With no clashes of dates with other championship events, it allows riders to better plan their campaigns too.

"It will be interesting also to see the 'clash of the veterans' too between Adam Youren, Hugh Lintott and Dougy Herbert, plus the juniors who will no doubt feature this year, riders such as Jake Wightman, Jackson Walker and Chris Dickson."

Rounds two, three and four of the national series will be held respectively in Mosgiel on April 3, Taranaki on April 16 and, finally, near Nelson on May 14.

Points only the best three of four rounds are counted, so riders will discard their worst result, ensuring the battle will go down to the wire.