British Prime Minister Boris Johnson is to launch an international "plan of action" to ensure Russia's invasion of Ukraine fails, including a flurry of diplomatic meetings next week, his office said on Saturday.

Johnson will seek to rally the international community to make a "renewed and concerted effort" to end Moscow's devastating war, and launch a six-point plan of action that he will detail on Sunday.

"In the days since Russia invaded Ukraine we have seen an unprecedented wave of international condemnation from across the globe," Downing Street said.

"Nations across the globe have imposed the largest ever package of sanctions against a major economy."

Russian President Vladimir "Putin must fail and must be seen to fail in this act of aggression," Johnson is to say. 

"It is not enough to express our support for the rules-based international order –- we must defend it against a sustained attempt to rewrite the rules by military force."

Johnson will host his Canadian and Dutch counterparts Justin Trudeau and Mark Rutte at Downing Street on Monday "for discussions on how to turn these commitments into a concerted campaign of solidarity with Ukraine".

On Tuesday, Johnson will hold talk with the leaders of the so-called Visegrad (V4) group of Hungary, Poland, the Czech Republic and Slovakia.

"These are countries already experiencing first-hand the humanitarian crisis rapidly engulfing the European continent," the prime minister's office said as hundreds of thousands of Ukrainians flee the fighting.

Johnson will tell the leaders that "the international community must come together under a six-point plan of action".

The plan includes mobilising an international humanitarian coalition, supporting Ukraine's self-defence and maximising economic pressure on Putin's regime.

It will also seek to prevent the "creeping normalisation of what Russia is doing", pursue diplomatic paths to de-escalation involving Ukraine and "begin a rapid campaign to strengthen security and resilience across the Euro-Atlantic area".