EnQuest's chief executive has said the windfall tax is continuing to cause "irreversible damage" to the energy industry.
The UK Government imposed an Energy Profit Levy (EPL) on profits made by oil and gas producers in 2022 which raised the overall tax rate to 75%.
Labour has announced it will increase the overall rate to 78% from November 1, as well as removing allowances to allow companies to offset investment spending against their tax bill.
Reporting to the markets this morning, EnQuest CEO Amjad Bseisu said: "We are disappointed with the ongoing application of the Energy Profits Levy despite operating in an environment where no windfall conditions exist.
"The UK energy industry needs a progressive tax regime that recognises the maturity of the North Sea and re-establishes the UK as a globally competitive investment basin.
"The oil and gas sector is the key to a Just Energy Transition, protecting the skills, jobs and resources required to deliver the decarbonisation projects of the future and, with stability and the right fiscal stimulus, can deliver material UK economic growth through billions of pounds of investment-ready projects.
"EnQuest has to date invested over £4billion in the UK and has the capacity and opportunities to do so again."
Mr Bseisu was speaking as EnQuest reported post-tax profit of $30.3m (£23.05m) for the first half of 2024.
Energy firm questions EPL timing
EnQuest's announcement follows the CEO of Harbour Energy questioning the timing of Labour's changes to the EPL.
Linda Cook said the "hurdle to attract investment" in the UK was now going to be higher, as her firm made a major overseas acquisition.
Harbour completed its $11.2bn (£8.54bn) takeover of Wintershall Dea on Tuesday, months prior that orginally expected.
The acquisition is a key pivot away from the UK North Sea, which Harbour depended on for about 90% of its output.
The company felt the brunt of the windfall tax when it was initially introduced in 2022, cutting 350 onshore jobs in the UK.
Ms Cook told the Financial Times: "Everyone understands that the UK will need oil and gas for many years to come, so why don’t we seem to want to use our own?
"It is better for investment, for energy security, for tax revenues, balance of trade and emissions."