Smith, 16, was also third to Begg and van Bentum in the senior-intermediate 10km points race. Begg went national record-hunting and put a 100m lead on van Bentum, with the chasing pack another 300m back. However, Ken Smith said timing-gear failure robbed her of a record.
Away from Begg, Rebecca Smith had a strong day in the intermediate ladies class winning the 1000m title with a commanding performance.
Smith claimed silver in the 500m after a slow start forced her to spend most of the race getting around Timaru's Dahna Penty, leaving it too late to catch Penty's town mate, Judah Kelly.
She was also third in the 300TT.
In other results for Wanganui club members, Chase Morpeth continued his domination of the primary boys' class, winning all three titles on offer, with Timaru's Ryan Caldwell providing the most competition.
Eden Smith, after a two-month injury break, picked up a couple of brave third placings in the junior boys' 300TT and 1000m races, while Steffan Teers showed improving speed in this grade.
Sophie Tang captured a bronze in the junior girls' class.
Renee Teers bagged a clutch of bronze medals in the juvenile girls' class, after finishing behind the Timaru pair of Ella Benson and Charlotte Clarke.
Renee Teers, Eugenia Lee and Caitlin Ferguson picked up the silver medal in the girls' (aged 9 to 12 years) 3000m relay behind the Timaru No1 combination.
The Wanganui senior ladies' team were disqualified from second place in their relay after missing an exchange.