Department of Conservation Whanganui biodiversity ranger Sara Treadgold said that although seals may look harmless and helpless, they are wild animals and will defend themselves if they feel threatened.
"It's important to keep dogs away from seals. If a dog makes direct contact with a seal, there is a potential for the dog to pass on diseases," Treadgold said.
"You may also encounter other seal species including the leopard seal. Leopard seals are very large animals. They could easily crush a person simply by rolling over and can move surprisingly quickly on land."
Seals usually arrive between August and November, but they have turned up as early as June.
So be aware and mindful when walking along Castlecliff, Kaiiwi and South Beach.
Seals may look distressed, scrawny and display signs of sneezing or coughing with weepy eyes, but that is natural for them - they really don't need any human help.
Treadgold said they will return to the water and swim away when they are rested and ready to go.
"My advice is, even if a seal looks injured, leave them alone.
"Seals are capable and resilient and given time and space, they usually find their way home."