About 4.20am on Monday, 10 to 15 cows were seen walking along Waitomo Caves Rd.
Two hours later seven large cows were spotted on Bush Rd near Ngatea.
Then about 4.30pm five cows were on the loose on State Highway 1 at Ohinewai.
"In addition to these we've had about half a dozen incidents of dogs on rural highways over the same period, including two incidents where the animals have had to be put down," Ms Grace said.
"To avoid tragedy it is important for land owners to ensure the integrity of their fences and farm gates, particularly in areas where stock are grazing paddocks next to roadsides," she said.
"Another important thing is motorists who have crashes where farm fences are damaged need to report it, not slink off in the middle of the night leaving a potential accident waiting to happen."
Motorists had responsibilities as well, she said.
"Drivers need to drive at a speed that allows them to react in time to unforeseen circumstances, and having proper lighting plays a major part."
Other incidents included:
• Three goats on the Thames Coast Rd about noon on August 14.
• A cow on SH2 near Steen Rd, Waitakaruru about 2pm last Sunday.
• Four cows wandering from Island Block Rd on to SH1 at Meremere about 4pm last Sunday.
• A large sheep on SH27 at Patetonga about 4.15pm last Sunday.
• A cow on Old Tauranga Rd near Waihi about 8am on Monday.
• A large deer on SH29 on the west side of the Kaimai summit about 9.45am on Monday.
• Three sheep on SH25 near Whitianga at 12.20pm on Monday.