Police have reacted with frustration after two young men entered the flooded Manning River on the mid-north coast of NSW on a double bed air mattress.

Police from Manning/Great lakes Local Area Command assisted SES in locating the men, who were found about 8.05pm on Sunday walking along Nowendoc Road after they managed to climb an embankment to safety.

Inspector John Sullivan said he was appalled and angered by the irresponsible behaviour.

"It is literally only days since we saw the tragic death of a young man in floodwaters, yet two young men have put their lives and the lives of their rescuers at risk," Insp Sullivan said.

"We have had police working day and night to keep our community safe and then we have to respond to a thoughtless incident such as this."

Insp Sullivan said people must act responsibly for their sake, the sake of their families and that of those who come to their aid.

"The message is simple: do not enter floodwater, be it over a road, a flooded creek, or a flooded river," he said.