The buy-to-let lender is stopping face-to-face meetings between business development managers (BDMs) and brokers, offering video calls instead.
It is also halting BDM attendance at large events and added that it had plans in place should it need to close its head office.
In a statement Keystone said it understood that many people, including brokers and customers, were worried about the effect of contracting the virus on themselves and their friends and families.
“At Keystone we are taking precautionary measures within the business to ensure the upmost safety of our staff and brokers,” it said.
“We have taken the decision to halt face to face meetings between our external BDMs and brokers. The team will instead be offering meetings via video call, as well as being contactable through email and telephone.
“Our BDMs will also not be attending any large events in an effort to reduce the risk posed to our staff and wider team.
“We are monitoring the guidelines set out by the UK government closely and will be ready to act in advance of these if necessary, to do so to reduce the risk to our staff and brokers.”
It added: “Should the head offices close due to coronavirus, all staff will work from home and we are confident that our services will continue as normal with no interruptions.”