Jeremy Corbyn has accused the Government of having no industrial strategy as redundancies mount in the crisis-stricken steel sector.
But David Cameron insisted his administration was doing everything it could to help, including changing procurement rules which already meant more public sector projects used British steel.
Speaking at Prime Minister's Questions, the Labour leader challenged: "Do you appreciate the devastating effects of the Government's non-intervention in the steel industry is having on so many people?"
Quoting a maintenance fitter on the Tata steelworks in Scunthorpe, Mr Corbyn said: "What are you going to do to support the steel industry and its workers who are now facing redundancy?
"Is it not time to walk the walk rather than talk the talk about the industrial strategy?"
Mr Cameron insisted: "We do want to help our steel industry and I will set out exactly how we will help the steel industry.
"It is in a very difficult situation, world prices have collapsed by more than half, the surplus capacity in the world is more than 50 times the UK output.
"But our plan to is to take action in four vital areas - procurement, energy costs, unfair competition and dumping, and tax and Government support."
Mr Cameron told MPs the change to the procurement rules had meant the Crossrail project had "almost exclusively" British steel.
Mr Corbyn said: "Isn't the real problem the Government doesn't actually have an industrial strategy to protect the most important industries in this country?
"If they had, they wouldn't have had to be dragged kicking and screaming to this House three times in the last eight days.
"Thousands of jobs have already gone in Redcar, Scunthorpe, Rotherham, Motherwell, Cambuslang, Wrexham, and across the West Midlands."
He challenged: "Isn't it time for concrete action today so there is Government intervention, there is support for our industry and we do have a viable steel industry for the long term, which this country desperately needs to have?"
Mr Cameron insisted he did want a strong and viable industry, and added: "On energy costs, we have already put £50 million into cutting energy costs and our plans will mean hundreds of millions extra to cut energy costs."
Following an intervention, Mr Cameron continued: "Last week in the House of Lords the Labour Party voted to add to energy bills by opposing the measures we are taking on wind power.
"So yes, we do have a strategy, we do have a plan, we should be working cross-party to deliver that plan."
Mr Corbyn accused the Prime Minister of failing to work in Europe to protect industry.
Mr Cameron replied: "We have been doing this for months, making sure we have proper action against dumping in the European Union, we have taken the cases to the European Commission, and we will continue to do so."