A winner of six races, including the Gr.2 Wellington Guineas (1400m) under the care of Allan Sharrock, Shamus joined the Murdoch's earlier this year for a change of scenery, notably with their use of Karioitahi Beach for training.
In his first appearance for the stable over 6 f at Te Rapa, the son of Shamexpress pressed on well for fifth behind Turn The Ace and has been allocated the 132lbs top-weight for the Porthouse Bar & Eatery Bream Bay Sprint (1400m) on Saturday.
"It was a nice first effort for us at Te Rapa, we're sort of feeling our way with him," Moira Murdoch said.
"He's got a fair bit of weight to carry, but I'm happy with his work and condition coming into the race.
"I did enter him in the sprinter's final at Ruakaka, I don't think he's really a mudder so we thought that would probably be the best option for him."
The ITM/GIB Sprinter's Final (1400m) has attracted some strong early nominations for the mid-July meeting, including Group One performing mare Malt Time, who is a key rival for Shamus in Saturday's race.
Joining Shamus on the journey north is Full Noise , a Turn Me Loose three-year-old contesting the Marsden Metals Group (1400m) at his second race-day appearance.
The gelding finished fourth on debut at Te Rapa on May 18 and is a half-brother to Mihaul, who won five of his six starts for the Murdoch's in a short career.
"He was a little bit lost left-handed at Te Rapa, so we've gone back to right-handed which he has trialled and had jump-outs over," she said.
"He's got not-to-bad a draw Tayla Mitchell and the step-up in distance will definitely suit him."
The partnership entered the winner's circle earlier in the week at Te Aroha with Flying Gib breaking maidens, and Murdoch has pencilled in a trip to Ruakaka for the El Roca filly in search of better ground.
"I was a bit worried about her in the heavy conditions on Monday, so I'm pleased we are heading to Ruakaka for her next effort," she said.
"It usually affords a pretty good surface at this time of the year, it's just a bit of a trek to get up there at the moment."