Freelance and contract workers fear they won't get paid if the coronavirus causes them to have to stay at home.
One anonymous freelance driver told the BBC's Wake up to Money: "If I become ill I'll have to work".
Self-isolating employees can access statutory sick pay from the first day they are off, but it's unclear if this applies to gig economy workers.
The UPHD drivers' union says "urgent action" is needed on working practices, including on sick pay.
It said: "Without access to worker rights such as minimum wage and sick pay, drivers who are infected may simply not be able to afford to stop working."
'Bread and butter'
Work and Pensions Minister Justin Tomlinson has said gig economy workers can apply for universal credit.
Some claimants have had to wait at least five weeks for the payments to start, although the Department for Work and Pensions pointed out that advances are "available immediately".
But the United Private Hire Drivers (UPHD) wants an immediate implementation of sick pay provision and the right to cancel high-risk work.
- Three days more sick pay for self-isolating workers
- Up to fifth of UK workers 'could be off sick at same time'
"Business is going down and down and down," an anonymous Manchester-based Uber driver told the BBC.
"I know our prime minister declared it for safety but I'm not entitled to sick pay so I don't know how to survive,"
"I need to work, this is my bread and butter. If I become ill I'll have to work, what am I going to do, my family will be starving? Everybody who is self employed is worried about what is going to happen."
And Mohammed, another Uber driver, based in London, told the BBC: "If I catch it I'm in Catch-22 because I can't afford not to work. I don't think the insurance will pay me... if I self-quarantine, I don't know if the insurance will cover it."
'Working to respond'
Uber said it would "compensate drivers when proper documentation shows they have been diagnosed with the coronavirus, or if they are placed in quarantine, asked to self isolate, or removed from the app for up to 14 days at the direction of a public health authority".
It also said it was in contact with local public health bodies and "will continue to follow their recommendations".
"We have a dedicated global team, guided by the advice of a consulting public health expert and public health organisations, working to respond as needed in each market where we operate around the world.
"To the best of our knowledge, there have been no cases of coronavirus spread between an Uber rider or driver."
Food delivery company Deliveroo says it will offer financial support to workers who are diagnosed with the virus or told to self-isolate.
It has sent its riders official guidelines on how to keep themselves safe, including best practice while they are out delivering food.
Delivery service DPD said: "All DPD drivers have a choice of being employed directly by DPD, being on a worker contract or being self-employed. Our employed drivers and those who opted-in to our worker contract will receive sick pay. Drivers who are self-employed need to use their substitute drivers, in the event of sickness, which is the standard procedure.
"We are looking at a range of ways to provide additional support for any DPD driver, should they need to self-isolate and we will be making a further announcement shortly."