The warning comes after the Christmas Day tragedy, when a 25-year-old Cambodian man, who was living Victoria, got into trouble in a notorious section of the river known as 'The Rocks' and drowned.

Acting Inspector Maggie Deall said near-drownings and fatal incidents are too common during the summer, especially for those who are not familiar with the dangers of inland waterways.

"The man wasn't familiar with the area ... and we find quite often it's people who are on holidays that get into trouble," she said.

"Wagga Beach is fantastic, it is number nine for best beaches in the country, but it can also be quite dangerous if you don't know the conditions."

It is because of the unpredictable conditions in the Murrumbidgee River, Acting Inspector Deall said people who cannot swim should not take their chances. She said even strong swimmers should not swim alone.

"Inland waterways can be some of the most dangerous in the world, just because they have swift moving currents, the temperatures underneath can be quite cold ... and (currents) can suck people under," she said.

Acting Inspector Deall said people can avoid getting into trouble by using common sense before entering the water.

"Check how fast the current is going, don't dive in and check the level of water by walking in," she said.

"If you get caught in a situation, the best idea is to point your toes down stream and just float. Don't swim out of the current because you will exhaust yourself."