Delivery firm Deliveroo has sparked a fresh row over the status of workers in the UK's gig economy after calling on the government to update legislation.
The company said changes would give self--employed people greater security while maintaining the flexibility they want.
Current employment laws prevent companies from extending some of the entitlements that are open to "workers" without calling into question the status of its riders, who are classed as self--employed, it said.
But unions countered that there was nothing stopping Deliveroo from paying its workforce the minimum wage and guaranteeing them basic rights like holiday and sick pay.
In evidence to a review by Matthew Taylor into the gig economy, Deliveroo said extending entitlements under the current law would undermine the flexibility that comes with riders being able to log in and log off at will, where they are paid according to work, not hours completed.
If riders were reclassified, they would be required to work in compulsory sessions arranged with Deliveroo in advance and to work exclusively for the company during those sessions.
Deliveroo is calling for a change in employment law that would allow it to offer new benefits to its riders, such as sick pay, insurance or shares for longstanding riders, describing it as a significant shift in UK employment practices.
Chief executive Will Shu said: "I still do deliveries every week so I know better than anyone the hard work that Deliveroo riders put in every day. It's only right that they're given the security they deserve whilst keeping the flexibility that they value.
"The on--demand economy has changed the way people work and live. We want an environment in which both workers and businesses benefit from the opportunities these changes provide."
Mr Taylor's review is expected to be published next week.
Maria Ludkin, legal director of the GMB, said: "The only people who think the law is out of date are the companies like Deliveroo, who are trying to subvert the law and exploit workers.
"The law, when properly enforced, does the job of ensuring working people are paid national minimum wage and given the most basic employment rights."
TUC general secretary Frances O'Grady said: "This reads like special pleading. Plenty of employers are able to provide genuine flexibility and security for their workforce. Deliveroo have no excuse for not following suit.
"The company's reluctance to offer benefits now is because they want to dodge wider employment and tax obligations by labelling staff as self-employed."
Neil Carberry, of the CBI, said: "It's absolutely right that businesses engage in the debate about how we foster a labour market that drives growth and opportunity for everyone.
"We warmly welcome Deliveroo's willingness to play a role in this, as it will help to move the discussion on to how to make the most of the opportunities of flexible forms of work, rather than demonising them as low quality."
Jason Moyer-Lee, of the Independent Workers' Union of Great Britain, said: "Deliveroo's claim that unfortunately the law prevents them from giving employment rights and benefits is utter hypocritical nonsense.
"In case after case the law has come down on the side of workers in the gig economy. There is nothing to suggest, either logically or legally, that flexibility and employment rights are mutually exclusive."