Trade body Offshore Energies UK (OEUK), formerly Oil and Gas UK, said at least 80 per cent of UK gas supplies and 70 per cent of oil will have to be sourced abroad by 2030 without new investment.
The UK used more gas from Norway than it did from the North Sea last year – the first time supplies from a single other country have been larger than domestic supply.
Energy security has become a key political issue in the aftermath of Russia's invasion of Ukraine.
OEUK's 2022 business outlook report warned production of oil and gas would fall by up to 15 per cent a year unless there was "rapid investment in new infrastructure".
It said investment had fallen from about £16 billion a year in 2014 to £5.5bn in 2019 and a predicted £4bn this year.
"The causes are varied but the UK’s complex regulatory environment, plus the political disagreements around issues like climate change and windfall taxes are all factors deterring investment," it added.
Gas and oil supplied three quarters of the UK’s total energy in 2021, about 2 per cent more than in 2020.
OEUK's report said failing to open new oil and gas resources would make the UK and other countries "increasingly reliant on Russia and Opec [Organization of the Petroleum Exporting Countries] member states", with "obvious implications for UK energy security".
Deirdre Michie, chief executive of OEUK, said: “Energy security is now a matter of national security.”
She told The Scotsman the controversial Cambo oil field off Shetland "and all other new projects like that" should go ahead.
The report said the North Sea sector remained "steadfast" in its commitment to net zero.
Ross Dornan, OEUK’s market intelligence manager, said: “The energy gap between what we produce ourselves and that which comes from other nations will keep growing unless we invest in exploration and production on the UK’s continental shelf.
“We must also accelerate the development of cleaner energy like hydrogen. Investment now will give us energy security in the years to come.”
Mr Dornan said the “main reason” for Norway now being the UK’s largest gas supplier was “the decline from our domestic production”, saying this dropped “significantly last year”.
He added: “We are in a fortunate position where we have good diversity of supply … but in the context of countries moving away from Russian supply, which is 40 per cent of the continent’s gas sources, those international sources are going to be more competitive than they have been.
“And if we want to be more reliant on imports we’re going to have to pay the price of that.”
Mr Dornan emphasised the importance of political support for the North Sea energy sector.
First Minister Nicola Sturgeon spoke out against Cambo last year, while the Greens, who have a power sharing agreement with the SNP, are outspoken in their opposition to new oil and gas extraction.
Maggie Chapman, the Greens’ economy spokeswoman, said: “The oil and gas industry spent decades denying the climate crisis and now they are simply ignoring it by attempting to double down on fossil fuel extraction.
"The UK Government should slap a windfall tax on the huge profits of these energy giants, not give them carte blanch to continue wrecking the planet and fleecing their customers.”
A Scottish Government spokesman said unlimited extraction of fossil fuels “is not consistent with our climate obligations”.
He added: “Recent actions by Russia only serve to highlight the importance of accelerating the transition to renewable energy sources.”
The spokesman said the equivalent of nearly 100 per cent of Scotland's electricity demand “already comes from renewable sources and we are focused on reducing reliance on fossil fuels”.
A UK Government spokesman said: "Energy security is our absolute priority. This is why, as part of our North Sea transition deal, we have committed joint investment with industry of up to £16bn by 2030 to maintain security of supply while boosting hydrogen production, carbon capture and other technologies to cut emissions.
“We cannot turn off North Sea oil and gas overnight as doing so would put energy security, British jobs and industries at risk, and we would be even more dependent on foreign imports.”