The Timaru builder won the shot put with a throw of 18.29m - the best distance at the ground for nearly two years.
Yang Liu (China) holds the Caledonian Ground record for the senior men's shot put with the 18.56m that he threw at the New Zealand championships early in 2011.
Walsh won the gold medal that day because foreign athletes are not eligible to win the New Zealand title.
Walsh (20) has won the New Zealand senior title for the past three years and had his best put of 19.33m when competing in Europe last winter.
He narrowly missed qualifying for the London Olympics but has set his sights on making the New Zealand team for next year's world championships in Moscow.
Walsh is coached for the throwing events by Ian Baird, in Timaru, and by New Zealand high performance coach Andrew Maclennan for strength training.
He finished sixth at the world youth championships in 2009 and competed in the world junior championships the following year.
He is confident of reaching the qualifying standard of 20.10m for next year's world championships in Moscow.
Walsh's sequence of throws in wet conditions at the Caledonian Ground on Saturday were 18.29m, foul, foul, foul, 17.25m, 18.12m.
Jerram Huston (Taieri) was runner-up with 14.43m and Dean Rusbatch (Taieri) third with 13.53m with the 7.26kg senior shot.
Rusbatch (18) won the junior men's shot put with the 6kg implement with a distance of 15.08m. He also won the junior men's hammer throw with a distance of 54.93m using the 6kg implement.
Todd Bates (Taieri) won the junior men's event using the 5kg implement with 51.56m.
New Zealand champion Marshall Hall (Taieri) had his first competitive throw of the season and won the discus with 49.56m.
He also had throws of 48.61m and 49.51m.
Walsh was runner-up with 46.12m and decathlete specialist Scott McLaren (Auckland) third with 42.97m.
Libby Jones (Taieri) won the women's aged 17 discus with 35.09m and AWD athlete Shaun Markham (King's) won the men's aged 17 event with 9.52m.
Ben Anderson (Caversham) sprinted home from the top of the straight to win the men's 800m in 1min 56.75sec from Daniel Balchin (New Brighton) 1min 57.18sec.
His father Geoff Anderson (Caversham) used the same tactics to win the masters men's event in 1min 22.16sec from Mark O'Donnell (Leith) 2min 22.72sec.
The Columba College team of Analise Cowie, Laura Saville, Zoey Flockton and Maddy Spence won the 4 x 100m in 53.39sec.
Daniel O'Shea (Hill City) beat New Zealand senior men's 400m champion Alex Jordan (Tasman) in the 300m in a time of 33.93sec.
Jordan was timed at 34.98sec.
