Mount Maunganui head lifeguard Callum Knox said he often saw parents sitting up on the dunes or grass verge at the beach while their preschoolers played at the water's edge 50-100m away.
"Ideally, if they're in the water, be in the water with them," Mr Knox said. "Arm's reach is a good standard to go by."
Now in his seventh season as a professional lifeguard, Mr Knox said if his team saw young children in the water or at the water's edge without supervision, they went to find the parents.
The water safety message comes as the number of beachgoers at the Mount has soared this week.
Mr Knox said more than 250 people were swimming between the flags on sunny days and the number was expected to rise to between 500 and 600 people over New Year.
That did not include the thousands who would flock to other parts of the Mount beach and the Bay's extensive coastline.
"It's tough to keep an eye on everyone," Mr Knox said.
"We're on to it, but there's only so much we can do."
He and Surf Life Saving eastern region lifeguard supervisor James Bray urged people to swim at patrolled beaches between the flags. They said the flagged areas were safest because they were chosen based on the conditions of the day.
Mr Bray said people who chose not to swim in those areas needed to learn to read rip currents.
"Always know your limits and err on the side of caution," he said. "What's safe on one day isn't necessary safe the next day."
Mr Knox added that learner surfers who were unsure if a spot was safe could ask a lifeguard.
More than 4000 lifeguards will be on duty at 80 beaches nationwide these holidays.
Ninety-five paid lifeguards are patrolling eastern region beaches from Hot Water Beach to Gisborne, and eight lifeguards will patrol the stretch of beach from Mauao to Tay St over New Year.
Paid weekday patrols at the Mount run until February 6, while volunteers do the weekends.
Boatie behaviour The Bay's love affair with boating is showing no signs of waning but the Coastguard and Maritime New Zealand are urging better safety among boaties.
"Coastguard's message is a simple one," said eastern region board chairman Stephen Clews.
"No one needs to die on the water. If before they go boating on our seas, lakes and rivers, people were to get familiar with New Zealand's Boating Safety Code they would go a long way to staying safe, no matter what kind of boat they use."
Mr Clews said skippers needed to stay within the limits of their vessels and experience. He recommended taking a Coastguard boating education course, including one on marine VHF radio training.
Research conducted this year found almost one in three New Zealand adults get out on the water but only 70 per cent wear a lifejacket at all times.
Nationwide, 24 people died in boating incidents this year, compared with 19 last year.
One death was in the Bay of Plenty - a 24-year-old man who went out fishing in a dinghy on Lake Rotorua with four others. None were wearing lifejackets but the others were rescued.
Maritime NZ said ownership of small vessels had increased and of 960,000 recreational vessels owned in New Zealand, more than half were small vessels, namely kayaks or canoes (320,000) and power boats less than 6m (224,000).
"Small vessels are far more vulnerable to sudden accidents and capsize," education and communication manager Pania Shingleton said. "You can quickly get in trouble due to bad weather, rough seas or suddenly ending up in the water."
The Research NZ study found kayakers and canoeists were most likely to always wear a lifejacket (83 per cent), compared with only 60 per cent of people in power boats and 55 per cent in sail boats.
Two-thirds of all recreational vessel users said it was very important to carry at least two ways to call for help, but only half actually did. Ms Shingleton said growing immigrant populations did not necessarily have a strong understanding of how to keep themselves safe on the water "but it's important to remember the majority of boaties who die are middle-aged, European men".
The Government has asked Maritime NZ to look at a possible national lifejacket rule.
