Outgunned, outmanned and outspent by Moscow, Kyiv has been forced to ramp up defence spending to support the war effort, with the conflict approaching the three-year mark.

President Volodymyr Zelensky on Friday approved Kyiv's 2025 budget plans that will see more than $50 billion -- or 60 percent of all expenditure -- go towards defence and security.

"The priority of the budget remains the defence of our state," Prime Minister Denys Shmygal said in a post on Telegram, confirming Zelensky had signed the budget into law.

A total of 2.23 trillion Ukrainian hryvnia ($54 billion), out of a general budget of 3.6 trillion hryvnia ($87 billion) will go towards defence and security, according to budget documents published by the finance ministry.

That covers payments for soldiers as well as arms production.

In a sign of the challenge faced by Kyiv in funding the war, Russia plans to spend more than double that amount on its own defence and security next year.

Moscow's draft budget earmarks 13.5 trillion rubles ($125 billion at Thursday's exchange rate) for defence -- and another 3.5 trillion rubles ($32 billion) for "domestic security".

Ukraine's defence spending in 2025 will only be slightly higher than this year's after the country upped its budgeted outlays for 2024 by a third in September.

Under the 2025 plans, Kyiv will also post a massive overall budget shortfall of 1.55 trillion hryvnia ($37 billion).

The economic devastation of the war alongside mass emigration has hit Kyiv's tax revenues, making the country reliant on support from Western countries and international financial institutions.

In addition to its own military outlays, Ukraine also receives tens of billions of dollars in direct military and humanitarian aid from its Western partners to plug the gap with Moscow's resources.

Donald Trump's victory in the US election has thrown that support into question, raising concerns in Kyiv about whether it can continue fighting Russia's advancing army without Washington's aid.