Defra says it has paid more than two-thirds of farmers their 2018 Basic Payment Scheme (BPS) money.
The Rural Payments Agency (RPA) has an internal target of paying at least 90% of eligible farmers and landowners their BPS cash by the end of December.
But the NFU understands that many of the two-thirds of farm businesses that have already received the BPS payments are farmers with smaller claims.
“Judging by the show of hands I’m seeing at recent NFU meetings I’d estimate around 50% of NFU members have been paid,” said NFU deputy president Guy Smith.
Mr Smith added: “It remains our hope that from January Defra will pay bridging loans to everyone who has not received their bridging payments – roughly 7-8% of claimants.
“Farmers desperately need this money to ease cash flow problems following a challenging year.”
By contrast, in Wales more than 95% of farm businesses were paid either their BPS claims or BPS loan applications during the first week of the 2018 payment window.
And in Scotland, more than 99% of BPS applicants have already benefited from interest-free BPS bridging loans, worth at least 70% of the value of claims. In Northern Ireland, 97% of farm businesses were paid their BPS money on 3 December, worth £85m in total.