"I watched the man [who died] get into the water and start to swim across.
"When he got to about halfway he appeared to be struggling and was turning over on to his back and then disappearing under the water a little."
She said at no time did he raise his hand or make it look like he needed help.
"He got near the shoreline and I waited for him to get up to walk to the shore and he didn't. I thought he might have been having a bit of a breather or a float around in the water before I realised it had been a long time since he had lifted his head.
"My next thought was that maybe he had a snorkel."
An estimated two or three minutes after the man reached the sand, Marshall said another man and his son who had also swum across the river stood up in the water and noticed the man floating.
"He called out to him and when he didn't get a response he went over, pulled him out and began CPR immediately."
Whakatāne Coastguard took police and medical staff and equipment across the river, returning on at least two occasions before stopping at the sand spit where the man was. A helicopter was also sent to the scene with the helicopter crew helping with resuscitation attempts, she said.
CPR was carried out for at least 45 minutes while a large number of onlookers watched from the Whakatāne side of the river. Youngsters playing in a park nearby could be heard laughing and yelling, oblivious to the events across the water.
About 10 people were seen gathered around the person who was lying on the sand on the Coastlands side of the river mouth, just metres from Whakatāne's famous statue of Wairaka - the Lady on the Rock.
A visibly upset woman was seen being comforted by locals and asked for someone to get a jersey from a suitcase on the back of her truck. On the back of the truck were two suitcases. She also asked someone to call members of her family.
When the first family member arrived, the woman lent into his open arms. A second car arrived and a woman began wailing and screaming across the water.
Not long after, emergency crews stopped trying to resuscitate the man and a white blanket was laid over him.
Police confirmed they had been called and medical attention was administered but the person died at the scene.
Fire and Emergency New Zealand and St John also attended but referred all questions to police.
A spokesman for the Whakatāne Coastguard said a member of the public raised the alarm, running into the office just after 2pm yesterday. A man had been seen floating in the water of the Whakatāne River, he said.
He said the Coastguard then called the emergency services.