"It put its head under the water and popped back up 20 seconds later, it was quite cool," Cullen Matthews said.

Cullen Matthews was working in a Hamilton park when he heard what sounded like a goat. Seconds later, a seal floated past.

Matthews was doing some work on the bank of the Waikato River in Featherstone Park, Flagstaff, about 8:30am Tuesday when he spotted the seal taking a morning swim.

"It put its head under the water and popped back up 20 seconds later, it was quite cool," he said. "It's gone a fair way to get up the river."

Department of Conservation Waikato spokesperson Des Williams was unaware of any reports of seal sightings in Hamilton but said they had been popping up at various locations in recent weeks.

DOC would only mount a rescue if one was found some distance from a waterway and needed assistance returning to the water.

Last month a juvenile fur seal ignited a flurry of phone calls to DOC after it made itself at home on the river walkway near the Peel Street bridge in Gisborne. DOC staff relocated the fur seal to the beach at Tapuwaewae o Rongokako Marine Reserve due to the number of dogs in the area.

Acting Conservation Services Manager, Don McLean said it was not usual for seals to be seen at this time of year.

"It is more common between August to November for newly-weaned fur seal pups and juveniles to come ashore, but it's just a resting up period for them before they again head out to sea in search of food."

McLean said while seals may look harmless and helpless they were wild animals and would defend themselves if they felt threatened.

"They can be carrying infectious diseases and can cause serious injuries."

LEAVE IT ALONE

If you encounter a seal on or near a beach, DOC advised to:

Always keep dogs on a leash, under control and away from seals.

Ensure you keep small children at a safe distance and under your control when watching seals.

Avoid getting closer than 20 metres.

Do not get between the seal and the sea.

Do not touch or feed the seal.

If you are concerned for the welfare of a seal, call DOC's 24 hour hotline 0800 362 468.