The Indian company has informed ministers that it needs support by July to confirm a potential multi-billion pound investment in green steelmaking facilities in South Wales.
The steelmaker expressed concern about the current level of assistance and criticized the recent budget as a missed opportunity to demonstrate its commitment to the industry.
Officials are in talks with Tata Steel and British Steel, the only other firms operating blast furnaces in the UK, to provide £300m each to boost investment in green technology.
One of the Port Talbot furnaces will close in the next few years and Tata Steel must decide whether to extend its life, close it or replace it with an electric steelmaking plant.
Without new technology, permanent closure could lead to thousands of job losses and further damage to the UK's struggling industry.
Energy costs have long been a concern for industrial firms such as steelmakers and the government has pledged to cut such costs through a "Supercharger" scheme, although it will not be implemented for at least a year.
A Department for Business and Trade spokesman said: "We provide comprehensive support to our vitally important steel sector on energy costs, fair public procurement and protecting the sector from unfair trade."
"Our recently announced British Industry Supercharger enables steelmakers to align with other major global economies by reducing energy costs. And our recent reform of trade solutions has been welcomed by the whole sector, including UK Steel, which described them as "extremely important.""
"This proves that we are listening to what the UK steel industry needs to maintain stability and support employment across the country."