Hamilton's Kayne Lamont, Takaka's Hamish Harwood, Mangakino's Maximus Purvis and Opunake's Taylar Rampton each set benchmarks when they dominated their respective classes at the opening round of the New Zealand Motocross Championships in Taranaki at the start of this month.

The second of four rounds is set for Rotorua this Sunday and each of these riders know they will again have to be at their best to keep their rivals at bay.

Of these four class leaders, only MX2 competitor Harwood is racing in defence of a national title, with Lamont chasing his first MX1 crown – although he did win the national MX2 title back in 2014.

Purvis will also chase his first senior National 125cc title and Rampton is set to lead the Women's Cup, a brand new separate two-round competition this season.

The performance so far of the 22-year-old Harwood is particularly noteworthy. He is something of an ironman, once again also racing in the MX1 class this season.

The former South Islander, now based in Royal Heights, West Auckland, was in dynamic form in Taranaki.

He was unbeaten in the MX2 class and then took a 300cc version of his bike to finish sixth overall against the 450cc riders in the MX1 grade as well.

His main focus again this year is on keeping hold of his MX2 crown, the MX1 class assault "just for fun" at this stage in his career.

Harwood finished the day in Taranaki 15 points clear of Taupo's national cross-country champion Brad Groombridge in the MX2 class, with visiting Australian Jay Wilson ending it third overall, just five points adrift of Groombridge.

Meanwhile, former Mangakino man Lamont was similarly dominant the MX1 class in Taranaki, scoring an impressive hat-trick of wins, and this earned him a solid 15-point advantage over Mount Maunganui's defending national champion Cody Cooper.

Second equal in the premier MX1 class after Taranaki is visiting Australian Kirk Gibbs, the Queenslander quite at home racing in New Zealand and sure to gather momentum as the series progresses.

Purvis came out on top in the National 125cc class in Taranaki, but visiting Australian Mason Semmens was right on his tail and actually won the last race of the day there.

Expect these two young men, and all the other 125cc riders too, to go full throttle again in Rotorua on Sunday.

In this weekend's second and final round of the Women's Cup competition, Rampton will be on the lookout for fight-backs from Rotorua riders Letitia Alabaster and Mel Patterson, respectively second and third in the standings, with these two challengers sure to be strong on home turf.

So this all sets the scene for what should be an enthralling day of racing on Sunday at the Phillips' farm property, just 20 kilometres south-west of Rotorua, on State Highway 30 at Horohoro.

The series next heads to Hawke's Bay for round three on March 11, with the fourth and final round in Taupo on Saturday, March 24.