“I think that Volodymyr Zelensky has done an absolutely amazing job of leading his country and leading world opinion in an appalling time,” Mr Johnson told ITV News at the summit in Bavaria.
Asked if he wanted to offer the Ukrainian leader a state visit, Mr Johnson said: “If he ever becomes free to leave and it makes sense for him to leave Ukraine, then obviously the UK would be only too honoured to host him.
“But the most important thing is for us to continue to be united here at the G7. And we are.”
The Sunday Times reported that ministers were considering offering Mr Zelensky a state visit, including a meeting with the Queen.
Tory officials would also like him to address the party’s conference in October, possibly via a video link, the newspaper reported.
Mr Johnson is using meetings at the G7 to urge counterparts to remain committed to supporting Ukraine and not to push for any peace deal which would see Vladimir Putin able to claim victory.
Despite concerns about the impact on the cost of living from increased energy and food prices, Mr Johnson said: “I think people in the G7, the leaders, can still see how vital it is that we stand together for freedom.
“Because if we don’t, we will pay a much, much higher price later on.
“If we allow Putin to get away with it, the consequences for the world in legitimating further aggression, further violence are much, much worse.”
Mr Zelensky, who will address G7 leaders by video link on Monday, pleaded for more air defence support from western allies.
After dozens of Russian missiles targeted Ukrainian towns and cities, he used his nightly address to say: “This confirms that sanctions packages against Russia are not enough, that Ukraine needs more armed assistance, and that air defence systems – the modern systems that our partners have – should be not in training areas or storage facilities, but in Ukraine, where they are now needed.
“Needed more than anywhere else in the world.”