She said children are not swimming the distances they were 25 years ago, and an increasing number cannot swim at all.
"I'm very committed to and passionate about reducing the drowning statistics, the number of people drowning per year," Sinden said.
She said a huge percentage of drownings are preventable "and so if we can educate people with more water safety skills to save their life, then we're going to reduce the number of preventable drownings".
Sinden has seen some close calls at local beaches over the years.
"I've seen children being taken out in the rips and then panicking. And so teaching rips and how to deal with them – just to stay relaxed and to go with it – is one of the really valuable things for kids to learn."
The community water safety day on October 28 is being held at the Toi Ohomai Aquatic Centre at the Windermere Campus.
It is a free event for all ages and abilities.
Everyone will get an opportunity to get into the pool and be taken through various lessons and exercises.
They will learn about what things they can use to float with if they are out at sea, rescue techniques, how to dive into the water safely from a boat or great height, and how to put a lifejacket on properly.
There will also be demonstrations, including a lesson on sailing and how to correct a capsized boat, and how to rescue someone from a kayak.
An Amazing Race-type competition will make the learning fun, with prizes to be won, and there will also be food and ice cream carts – and a DJ.
Sinden said she is hoping a few hundred people will take part in the event.
"We're surrounded by water. Our lifestyle and the activities that we do surround water. And so I think it's a necessity. We have to teach people the skills to be able to protect themselves and stay safe in the water."
The event will run from 9am-2pm.
