Divers are searching the river and a police helicopter has been circling the area close to where Nicola Bulley went missing more than three weeks ago.
A road has been cordoned off along the River Wyre in St Michael’s on Wyre, Lancashire, as has a footpath.
It has been the focus of an intensive search operation since Ms Bulley, 45, was last seen at about 9.10am on 27 January while walking her dog.
Sky News correspondent Inzamam Rashid said the helicopter was in the air for about 25 minutes.
A police drone has also been in use.
The search site is about a mile from where Ms Bulley was lasted spotted.
“There is a significant police presence at one section of the river,” Rashid said.
The senior investigating officer, Detective Superintendent Rebecca Smith, is among them, he added.
Officers have said their main working hypothesis is that the mother-of-two fell into the river, but her friends and family claimed there was “no evidence whatsoever” to support that theory.
Concerns have been expressed by Prime Minister Rishi Sunak and Home Secretary Suella Braverman about the release of personal information about Ms Bulley.
Police said she had suffered “significant issues with alcohol” which had been brought on by “ongoing struggles with the menopause”.
But Ms Bulley’s family said they were “aware beforehand that Lancashire Police released a statement with some personal details about our Nikki”.
They said: “Although we know that Nikki would not have wanted this, there are people out there speculating and threatening to sell stories about her. This is appalling and needs to stop.
“The public focus has to be on finding her and not making up wild theories about her personal life.”
The dog walker who found Nicola Bulley’s phone on a bench told Sky News he thought “this is not right” when he saw the device on the morning of her disappearance.
The man, who gave his name as Ron, also said he saw the wallpaper on the phone showing Ms Bulley and her partner, Paul Ansell, before police were called and she was reported missing.
He said he had given a full statement to the police.