The production near threshold of isoscalar pion pairs in the pd -> 3He(pipi)^0 reaction is estimated in a two-step model which successfully describesthe production of eta, omega and eta' mesons. A virtual pion beam, generatedthrough an NN -> d pi reaction on one of the nucleons in the deuteron, producesa second pion via a pi N -> pi pi N reaction on the other nucleon. Using thesame scale factor as for heavy meson production, the model reproduces the totalpi^0 pi^0 production rate determined at an excess energy of 37 MeV. There aresome indications in the data for a suppression of events with low pi pi masses,as in the pi^- p -> pi^0 pi^0 n reaction, and this is confirmed within themodel. The model suggests that a significant fraction of the charged pionproduction in the p d -> 3He pi^+ pi^- reaction at Q=70 MeV might be associatedwith isoscalar pion pairs, though this does not explain the strong dependenceobserved on the pi^+ pi^- relative momentum angle.