Liz Truss is set to tell Nato foreign ministers that the “age of engagement with Russia is over”.
The UK foreign secretary will also declare that an agreement between Nato and Moscow, under which the two sides “do not consider each other as adversaries”, is dead.
Ms Truss will attend a working dinner with Nato ministers in Brussels on Wednesday, where she is expected to say the alliance must toughen its response and not allow security vacuums to emerge.
"We need a new approach to security in Europe based on resilience, defence and deterrence," she is expected to say, according to excerpts of her address released early.
"There is no time for false comfort. Russia is not retreating, but regrouping and repositioning to push harder in the east and south of Ukraine."
Ms Truss is expected to push the importance of continuing to arm Ukraine and toughening sanctions, as the UK announced more penalties on Wednesday.
Asset freezes have been imposed on Sberbank, Russia’s largest lender, and the Credit Bank of Moscow.
All new outward investment to Russia has been banned and the UK has also committed to end all imports of Russian coal and oil by the end of the year, with gas to follow as soon as possible.
Imports of Russian iron and steel products will be banned and another eight oligarchs have been added to the sanctions list.
Ms Truss said they are “some of our toughest sanctions yet”.
At the Nato meeting, she is expected to urge more support for countries such as Georgia, Moldova, Sweden and Finland.
Ms Truss is also expected to say the Nato-Russia Founding Act, in which it was declared the two sides “do not consider each other as adversaries”, is dead.
The agreement, signed in 1997, aimed to increase security and stability.
