Some 35% of the steel used to build the Navy's new fleet of eight frigates will be sourced from Britain, a Defence Minister has said.
The majority of the steel used to build the new Type 26 global combat ships will come from the UK and Sweden but only around a third will be sourced domestically, Harriet Baldwin said.
The Community steelworkers' union said the proportion of British steel used is "not good enough".
Earlier this month, a £3.7 billion contract was signed to build the first three ships and work will start at BAE Systems' yards on the River Clyde in Glasgow this summer, securing 1,700 jobs in Scotland and a further 1,700 in the supply chain across the UK.
A total of eight ships are to be built in the fleet, with the contract for the second batch of five ships to be negotiated in the early 2020s.
Replying to written parliamentary questions from Labour MP Stephen Kinnock, Ms Baldwin said: "Around 4,000 tonnes of steel will be required to build each Type 26 frigate.
"Steel will be sourced principally from the UK and Sweden. For some grades of plate steel, the combination of thickness, size and flatness specifications needed for the Type 26 frigates mean that the steel cannot be sourced in its entirety in the UK."
In another answer she said 35% of the steel will come from the UK.
Ms Baldwin said: "Responsibility for sourcing steel for the Type 26 Frigates rests with BAE Systems as the contractor. In accordance with Government guidelines on the procurement of steel, the company has run a competition to select a supplier of steel for the programme, and an announcement is expected shortly.
"UK steel suppliers have been strongly encouraged to bid in line with the Government's Procurement Policy Notice concerning the procurement of steel for major Government projects. This pipeline is published on GOV.UK. The MOD will continue to carry out early market engagement and forecast our steel requirements for shipbuilding through the UK Government Steel Pipeline.
"We expect that around 35% of the steel required to build each Type 26 frigate will be sourced from UK suppliers in Scotland and Scunthorpe; approximately 1,400 tonnes per ship."
Community steelworkers' union boss Roy Rickhuss told the Mirror: "British steel is some of the best in the world, and our Government should be using this project to help British steelworkers.
"It's not good enough for the Government to say we can't make the right sort of steel. If we had a proper industrial strategy, our steelworks would be equipped to meet the challenges.
"Steelworkers have made big sacrifices over the past few years; it's now time for the Government to bring forward a strategy for steel that supports our industry and our steel communities."
BAE told the newspaper: "Following an open competitive bid process, Yorkshire-based Dent Steel UK has been selected to source steel for the first three ships. Approximately 50% of the value of steel will be British, equating to around 35% of the overall weight."