The Department of Conservation is calling on beach-goers to report sightings of sea lions and their pups this summer.
New Zealand sea lions are critically endangered and enjoy Otago's sandy beaches to sleep, mate and play so it was likely people would encounter them on the beach, Doc says.
Sea lions have been breeding on Otago's coast since 1994, when the first pup was born on the mainland in 200 years.
Mid-summer is the time of year female sea lions have their pups and in order to protect themselves from their male counterparts, they hide on beaches and in sand dunes.
About four or five pups were born on Otago beaches each summer, which means they were vulnerable to disturbance from people and especially from dogs, Coastal Otago biodiversity programme manager David Agnew said.
Last summer one female sea lion, Gem, gave birth to a pup (Marama) on the busy Tomahawk Beach. Vulnerable to possible dog attacks, Gem and Marama were moved by Doc to a quieter location.
The move was successful and the pair had regularly been sighted throughout the year, he said.
People who came across sea lions needed to be aware that, unlike fur seals, they were not afraid of people and the best approach was to back away slowly.
''Rather than run away, they will charge at you if you get too close. Keep a reasonable distance and they are unlikely to bother you, especially when they are resting.''
A charge was usually a bluff to indicate that someone had invaded their personal space and if people backed off slowly, the sea lion was unlikely to pursue far.
The same went for sea lions in the water, Mr Agnew said. People should not engage with the creature, but rather move slowly away while staying horizontal in the water.
''Be really boring. The sea lion will divide his attention between everyone in a group, so there will be more time to relax and enjoy the experience if you are swimming with others.''
Fishermen should not encourage sea lions and should clean fish well out to sea or keep offal on board until they reached shore.
''It is an offence to feed marine mammals.''
People are urged to call the 0800 DOCHOT line (0800 362 468) with any reports of sea lions.