Welsh economy minister Edwina Hart said despite criticism of UK ministers, her counterparts in London know how important the industry is.
She met UK Business Secretary Sajid Javid on his visit to Port Talbot steelworks on Friday.
Tata Steel has said it would sell its UK business, putting thousands of jobs at risk.
Mr Javid said he had been concerned at talk of a time-frame for the sale of three to four weeks, but says there is now an understanding it is "much longer" than that.
Ms Hart told the BBC: "It's very important to recognise in UK terms we can't allow the steel industry to go.
"What happens to defence contracts, what happens now in terms of nuclear? We need a steel industry. I think the UK government is as aware of that as us.
"We've got to be hopeful, because it's important we keep steel, and that is what both governments are trying to do, to ensure we've got the best results in terms of the purchase of the plant."
Port Talbot has the largest steelworks in the UK, with 4,000 jobs at risk.
Tata has other Welsh plants at Trostre, Shotton, Llanwern and Newport, while UK plants in Rotherham and Corby are also affected.
Eluned Parrott, Liberal Democrat economy spokeswoman, said: "It is all very well for Sajid Javid to come here and promise action, but his words of support for the steel industry are in stark contrast to his record.
"The fact is that Mr Javid and his Tory colleagues have done nothing to mitigate this crisis."
Plaid Cymru leader Leanne Wood said: "Inaction and indifference by governments at both ends of the M4 mean that months of lost time have gone by in which decisive action could have been taken."
A UKIP Wales spokesman said Mr Javid arrives in Wales "with a long face but an empty portfolio".
"As long as we are members of the EU we cannot decide to change our tariffs on Chinese steel and we are condemned to paying artificially expanded rates for energy."
Britain Stronger In Europe, which is campaigning for the UK to stay in the EU, said the European Commission had a record 37 anti-dumping measures in place, with 16 of those specifically targeting Chinese imports.
The UK and Welsh governments are working to keep steel production in Britain, a minister has said.