Centre Dillon Adrole and veteran midfield partner Ace Malo then crossed for a 20-0 lead at halftime.
Kaierau kept it up in the second stanza, as both Robinson and Adrole would go on to claim hat tricks, while flanker Cade Robinson made a family affair with his try - Marist having to play part of the half with 14 after reserve Simon Dibben's sinbinning.
Marist's only consolation was they have not lost ground in the chase to finish fourth after Ngamatapouri's wheels fell off in the 90-0 hammering by Border, who continue to signal ominous tones for the team's that travel to Dallison Park.
Ngamatapouri had led the table after two weeks, but that is already looking far away as Border ran in 14 tries, with winger Tom Symes picking up a hatrick, while on the other side the lightning Vereniki Tikoisolomone got a double.
Flanker Angus Middleton also scored two tries and halfback Lindsay Horrocks continued his streak by scoring for the fifth consecutive game.
First-five Craig Clare added a try and seven conversions before handing the kicking duties over to Tyrone Albert.
Ngamatapouri and Marist will need to pick themselves up, as their Spriggens Park clash this Saturday could go a long way towards securing fourth spot by the end of the second round.
While their Premier's had no joy, Marist Celtic had reason to celebrate at the Country Club after a crucial comeback win over Gemini Pepper Construction Kaierau, 24-21.
Down 14-5 at halftime in the top of the table clash for Tasman Tanning Senior, Celtic got home for their fifth bonus point win, now half way through their games in the race to finish in the Top 2 for the 11-team grade.
The Stihl Shop Wanganui Challenge Shield holders Harvey Round Motors Ratana had a vested interest in the outcome of that match, as they closed up to Kaierau while also dealing Kelso Hunterville's hopes of continued championship success a big blow, 39-15 in Hunterville.
Black Bull Liquor Pirates won't have much say in the title race, but their supporters couldn't have cared less after watching a great comeback for a 34-32 win in the Spriggens Park derby with Marist Buffalos.
Counties had drawn with Pirates the previous weekend, and rebounded with a 27-12 victory over Border in Waverley, while Utiku Old Boys also travelled well – beating Speirs Food Marton 36-20 at Marton Park.
Results, August 1
Tasman Tanning Premier, Round 5
Grand Hotel Challenge Shield – Wanganui Car Centre Kaierau 54 (Ethan Robinson 3, Dion Adrole 3, Cade Robinson, Karl Pascoe, Ace Malo tries; Robinson pen, con, Logan Henry 2 con) by Dave Hoskin Carriers Marist 0. HT: 20-0.
Waverley Harvesting Border 90 (Tom Symes 3, Vereniki Tikoisolomone 2, Angus Milddleton 2, Ross McDonald, Hamish Mellow, Semi Vodosese, Lindsay Horrocks, Craig Clare, Isaiah Hooper, Alekesio Vakororogo tries; Clare 7 con, Tyrone Albert 3 con) bt Settlers Honey Ngamatapouri 0. HT: 40-0.
Byford's Readimix Taihape 45 (Dylan Gallien 2, Tyler Rogers-Holden 2, Ollie Rhodes, Ryan Karatau, Matt Brown trie;, Dane Whale 5 con) bt McCarthy Transport Ruapehu 24 (Kahl Elers-Green 2, Takarangi Metekingi 2 tries; Tuhirangi Akapita con, Logan Blackburn con). HT: 21-5.
Senior championship, Round 5
At Spriggens Park: Black Bull Liquor Pirates bt Marist Buffalo's 34-32. HT: 24-12 Marist.
At Kaierau Country Club: Marist Celtic bt Gemini Pepper Construction Kaierau 24-21. HT: 14-5 Kaierau.
At Dallison Park: Counties bt Border 27-12. HT: 27-0
At Marton Park: Utiku OB bt Speirs Food Marton 36-20. HT: 15-8.
At Hunterville (Stihl Shop Wanganui Challenge Shield) – Harvey Round Motors Ratana bt Kelso Hunterville 39-15. HT: 21-5.
Bennett's Taihape bye.
Around the grounds:
Metro
The St Johns Wanganui Metro Colts are looking in top form heading into this coming weekend's Manawatu club semifinals after a 78-0 shutout of winless College Old Boys in the Cooks Gardens double header on Saturday. In the last competition game for their debut season, the St Johns Wanganui Women gave a good account of themselves against the undefeated Feilding Old Boys-Oroua, taking a 44-0 loss.
Collegiate
The Whanganui Collegiate 1st XV will be looking to keep momentum going heading into their first home game of the Central North Island competition with Rathkeale College on Wednesday. Collegiate won their opening away game 29-15 against Lindisfarne College last Tuesday. Due to Covid-19 delays, CNI has been split into two regional pools of five teams, with the Top 2 from each pool making the semifinals.
Ref course
The WRFU is offering a second Associate Referee (AR) course at the union offices at Cooks Gardens on Wednesday at 6pm. The course will take roughly 90 minutes and is open to anyone. Message the WRFU Facebook page or email tyrone.kemp@wanganuirugby.co.nz for further information.