The panel was discovered after high winds last weekend and has forced the closure of the adjacent A320 Victoria Way while further checks and repair work are carried-out.
The road has been shut numerous times due to external panel issues during the construction of the hotel and since it opened last Autumn.
The A320 had only reopened in mid January after being shut for similar issues last December.
Cllr Ann-Marie Barker, Leader of Woking Borough Council, said: “Thank you to the emergency services who attended the scene so swiftly when a loose panel was identified on the Hilton Hotel.
“Whilst the closure of Victoria Way is extremely disruptive and frustrating, safety is everyone’s number one priority.
“I’m very angry that another panel has failed on the hotel building despite assurances from SRM earlier this month that the panels were now safe and secure.
“A course of action has been identified to put things right and the council and Victoria Square Woking Ltd are urging SRM to progress this as quickly as possible.
“In the meantime, I am committed to keeping you updated and pushing for a permanent resolution so we are not in this situation every time there is an extreme weather event.”
A spokesperson for Sir Robert McAlpine said: “In the aftermath of Storm Herminia on Sunday, which followed immediately after the powerful Storm Eowyn on Friday, one cladding panel was found to be loose on the western elevation of the hotel building.
“In order to ensure the safety of drivers and pedestrians, Victoria Way will need to remain closed until the exterior panel is fixed and further checks have been completed to a number of panels across the building. This will be carried out as soon as the wind speeds are within the safe working limits.
“It is not possible to confirm how long we will require Victoria Way to be closed at this stage, but it is anticipated to be a number of weeks and we will provide further updates as our works progress.
“We apologise for the disruption that the closure of Victoria Way is causing. The hotel and the rest of Victoria Place remain open for business as usual during this period.”
Woking MP Will Forster has also written to McAlpine chief executive Neil Martin demanding a detailed plan for remediation work.