Emissions totalled 47.5 million tonnes of CO2 equivalents, an increase of more than three million tonnes compared to 2023, the agency said in a statement.

The agency noted that it was the largest yearly increase "since 1990, with the exception of 2010, when the recovery from the financial crisis took place."

"This was mainly due to increased use of fossil diesel in road traffic and work machines," the agency said, noting that the domestic transport sector was now the largest source of emissions in Sweden.

Lowered taxes on fuel was a key campaign promise of the conservative coalition government propped by the anti-immigration Sweden Democrats (SD).

The government also eased Sweden's "reduction obligation" -- which requires petrol and diesel producers to mix in renewable fuels.

Environmental groups and other government agencies have warned that Sweden may not meet its various emissions goals.

"Over the past 15 years, the trend has been towards lowered emissions, and we have looked set to achieve both the national interim target and the EU commitment for 2030. The increase in emissions in 2024 has made that more difficult," Roger Sedin, head of the agency's climate target unit, said in a statement.

The Scandinavian country has set a target of carbon neutrality for 2045, five years ahead of the EU.