Port Stephens' MP Kate Washington and local community groups have renewed their calls for the Myall River's "short cut" to be dredged, after a Hawks Nest man rescued a dolphin off a sandbank at the eastern entrance to the river last week.
James Condon said he was returning home from a fishing trip via the passage on Thursday when he spotted a dolphin on a sandbank at the entrance.
"When we got him there was a five to eight metre radius of sand around him. He must have been up there for a bit. He didn't look to be moving but when I got close he gave off a little squeak. He was that dry and in a bad way," he said.
Mr Condon said he had to drag the creature down to the water, estimating it weighed about 90 kilos.
"It was about ten minutes in the water before he got going. He swam right beside my legs for about 20 or 30 metres and then took off. It was amazing," Mr Condon said.
MP Kate Washington said she could not comprehend the incident as "anything other than the silting up of a dolphin navigation channel".
She said she had not heard of any other recent incidents of dolphins becoming stranded near the short cut.
"Since the 2015 dredging when the short cut was made navigable there has been an increased sighting of marine life and dolphins in and up the river," she said.
"There has been an increased flushing of the water through the channel. It appears the dredging has worked in the way the residents anticipated it would.
"Since then they have wanted a full plan so it remains open."
Ms Washington said there was an "immensity of frustration" in the community that there was no single authority responsible for maintaining the entrance, which is managed by a mix of local, state and federal government departments.
"I'll continue to call on state government to improve the processes for the approval of dredging and then for them to actually fund it," she said.
Gordon Grainger of Myall River Action Group said two families of dolphins had been using the river on a "daily basis" since it was cleared.
He said back in 2013, before the river was dredged, he witnessed a group of dolphins getting caught on a sandbank at the short cut, but they freed themselves.
"With the rapidly closing entrance they are now in jeopardy, as is the health of our river system," Mr Grainger said.
"I would like to see it dredged in six months and certainly in no longer than 12."
Mr Condon said he sometimes struggled to get his boat through the short cut at low tide, and "bottomed out" in the river the day he saw the dolphin.
"I dare say it [the stranded dolphin] would be something to do with the low tide and the banks that are there because they are just getting bigger and bigger," he said.