The trash-talking stops when the start-gate drops in Taranaki this weekend as motocross riders fight for national glory starts.

It's been four years since Taranaki last hosted a round of the New Zealand Motocross Championships, but this Sunday the popular Barrett Road Motorcycle Park facility, on the outskirts of New Plymouth, will again echo with the sound of top-level dirt bike racing.

Mount Maunganui's Cody Cooper. Photo: Andy McGechan, BikesportNZ.com

New Zealand's elite motocross riders have travelled the country in recent months to flex their muscles and prove that they're contenders for a national crown but all those hours of training, kilometres of travel and exhausting days of high-speed and high-risk racing perhaps count for little.

It's only the racing that happens during the next few weeks that really matters.

The first of four rounds in this year's JT Racing-sponsored New Zealand motocross championships is set for the Barrett Road Motorcycle Park facility in New Plymouth.

So many different riders have dominated at the many major events staged around NZ since before Christmas and any of these men could be expected to feature on Sunday.

In the 450cc MX1 class, it was Taupo's Brad Groombridge (Suzuki) who won the MX Fest at Taupo in October and then again at the Auckland motocross championships in early December.

His Suzuki team-mate, Mount Maunganui's Rhys Carter, celebrated his return to action following an injury lay-off to win the MX1 class at the annual Whakatane Summercross just after Christmas and Waitakere's Ethan Martens (Yamaha) was top dog in the MX1 class at the Valley Championships at Patetonga just a couple of weekends later.

Queenstown's Scott Columb (Yamaha) won the feature race at the King of the Mountain motocross in Taranaki just seven days later, edging out Martens, Carter and Rotorua's John Phillips (Honda) in the process.

But, significantly, the most recent winners have been defending national MX1 champion Cody Cooper, who won all three races in the MX1 class at the annual New Zealand motocross grand prix at Woodville just over a week ago, and Australian KTM rider Kirk Gibbs, who stole the feature race win at Woodville.

That's six different riders and four different bike brands that have featured on the top of the podium over the past few months and any one of these riders could expect to be leading the points' standings when the dust or mud clears in Taranaki on Sunday.

The same could almost be said of the MX2 (250cc) class contenders, although national champion Kayne Lamont (Yamaha), of Mangakino, crashed heavily while training last week and will not be able to defend his title.

That opens it up for two-time former national champion Mike Phillips (Honda), of Rotorua, fellow Kiwi international Josiah Natzke (KTM), of Hamilton, both riders who have impressed in the class recently.

The smallest engine capacity bike category, the national 125cc class, probably still belongs to defending champion and two-class campaigner Natzke, although he can expect fierce opposition from riders such as Ngatea's Ben Broad (KTM), Taupo brothers Cohen and Wyatt Chase (both Yamaha), Nelson's Reece Walker (Yamaha) and Pukekohe's Kurtis Lilly (Husqvarna).

The slopes of Taranaki have been a graveyard for many campaigns in the past, a moment's inattention or a slice of bad luck causing pain and costing vital points.

After racing Taranaki, the series moves to Pleasant Point, near Timaru for round two on February 22, with rounds three and four set for Rotorua and Pukekohe respectively, on March 8 and March 15.