Farage, a leading campaigner for Brexit, is one of the most influential politicians in modern British history.
For more than a year, his Reform party has led almost every national opinion poll and won local elections, posing a threat to the century-old dominance of the Labour and Conservative parties.
But Farage in recent weeks has appeared irritable and uneasy after it was revealed he had accepted a Stg5 million ($A9.6 million) gift from a billionaire crypto investor and not disclosed it.
He is being investigated by parliament's standards watchdog over the Stg5 million donation and has also been referred to the regulator over a report of separate donations.
"I will make a statement on my future in public life at 2pm (11pm AEST)," Farage said in a post on X on Tuesday.
The revelation around the donation has sparked heavy scrutiny of Farage's finances and property.
In recent days he has complained about reporters harassing his family and press intrusion.
If Farage is found to have committed a serious breach of parliamentary disclosure rules, he could be suspended from the House of Commons.
A suspension of 10 days or more could trigger a recall petition, potentially forcing a by-election in his parliamentary seat.
Farage had served as the leader of the UK Independence Party and resigned after the 2016 Brexit referendum, saying at the time that his political ambition had been achieved.
He later returned and launched the Brexit Party, which was subsequently rebranded as Reform UK.
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