UKAD chairman David Kenworthy told the BBC that they had been warned to expect cuts of up to 25 percent, which could result in an end to testing.
"UKAD would be in jeopardy if we had large cuts like that because the purpose for which we're here, I'm not sure we could fulfil it properly," he said.
"We've got to have the time and means to try to make up that income if we're to survive, if we don't the integrity of UK sport is at risk.
"That would be desperate. With the amount of money invested in the integrity of sport over the years, to get it to where it is, that would be a huge blow to UK plc."
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Doping is becoming an increasingly contentious issue with a number of high profile sportsmen and women facing doping claims in the past year.
UKAD conducted more than 8,000 tests across 40 sports last year.
"Something's got to give so the testing would certainly go," Kenworthy added.
"Tests are very expensive. The standard urine sample to be tested costs 371 pounds ($568.45), the athlete biological passport costs 439 pounds for each test.
"I think we'd be almost dead in the water frankly, you can't function on that basis. It would be an appalling cut and appalling waste of our experience that we have built up."
The BBC quoted a government spokesperson saying that decisions on future funding would not be announced before a spending review on Nov. 25.
"We have also been clear that all parts of the public sector will be required to find savings through efficiencies and reforming the way things are done so that we deliver more with less," the spokesperson added.
(Reporting by Toby Davis; editing by Tony Jimenez)
