Results of the studies on the temperature-dependent magnetic susceptibility and electrical resistivity of the compounds Dy6-xY xAl3Si (x=0, 3, and 5) is presented in the work. AC magnetic susceptibility studies show three magnetic orderings at 110, 47.5 and 30 K for the compound Dy6Al3Si and the peak corresponding to the low temperature (30 K) shows frequency-dependent behavior varying from 30 K at 8 Hz to 31 K at 33 Hz, 32.6 K at 222 Hz and 33.6 K at 666 Hz. As the Dy site is substituted by non-magnetic Y3+ ion, the magnetic ordering temperature decreases. Pronounced anomalies are observed in the resistivity behavior of the compounds in the neighborhood of the magnetic ordering temperatures. Results reveal the presence of frustrated exchange interactions in the system. The results could be accounted to the unique crystal structure of the system having three different rare-earth sites with different magnetic environments. © 2005 Published by Elsevier B.V.