The Prime Minister insisted “no option” was off the table, but said people would have to wait for the UK Government to decide.
His comments came just hours after a minister had defended the response to the cost-of-living crisis, saying the Government would not “rush” any decision.
Speaking at a school in St Mary Cray, south-east London, on Monday, Mr Johnson said: “No option is off the table, let’s be absolutely clear about that.
“I’m not attracted, intrinsically, to new taxes.
"But as I have said throughout, we have got to do what we can – and we will – to look after people through the aftershocks of Covid, through the current pressures on energy prices that we are seeing post-Covid and with what’s going on in Russia and we are going to put our arms round people, just as we did during the pandemic.”
Mr Johnson said there was “more that we are going to do”, but “you’ll just have to wait a little bit longer”.
Earlier a minister said the UK Government was “not going to rush into action” on making a decision over a possible windfall tax.
Asked when Chancellor Rishi Sunak might decide on the fiscal policy, told BBC Radio 4’s Today programme: “That is a question for the Chancellor.
“We obviously recognise that we are in a situation which is fast developing and we want to make sure that we are supporting people ahead of what will likely be a challenging autumn and winter ahead.
“I’m not going to set a specific timetable for that, but the Chancellor is clear that we are looking at the situation with real urgency and intent.
“And it is against this backdrop that people can be reassured that the Government is on the case.
“We are not going to rush into action, but at the same time nor are we going to sit here and not provide the support that is needed given the severity of the situation.”
Not ruling out a tax, Mr Johnson added: “The sector is realising enormous profits at the moment.
“If those profits are not directed in a way in which is productive for the real economy, then clearly all options are on the table.”
Sir Keir said: “Here in Sainsbury’s, both staff and customers have been talking about the cost of living and the prices that they can’t afford.
“Part of the answer is staring the Prime Minister in the face and that’s Labour’s plan for windfall tax on oil and gas companies and using that money directly to reduce bills by up to £600 for those who need it most.
“But what’s the Government doing? It’s dithering, it’s delaying. Last week they voted against a windfall tax, now they’re saying they’re looking at windfall tax.
“They need to get a grip on this situation, because every day they dither and delay, more people are struggling, really struggling, with their bills.”