Your employer can only stop paying you or make an immediate change to your job if there is a clause in your employment agreement that says this.
This is usually called a “business interruption clause,” and is specific to situations of natural disaster or other unexpected events where your work has to temporarily close.
If your employment agreement has a business interruption clause, your employer still needs to consult with you about stopping your pay. This has to include looking at alternative ways to keep you working while the business is temporarily closed.
If your employment agreement doesn’t have a business interruption clause, they have to continue paying you as usual. You can still be required to take annual leave, but your employer has to give you at least 14 days’ notice.
If the changes at your work become permanent, your employer may start a redundancy process (see: “If your workplace is permanently affected by flooding” below).