MPs using unpaid interns are sending a message to UK businesses that "exploiting" young workers is acceptable, a Conservative has claimed.
Alec Shelbrooke said more than 20 MPs are advertising unpaid internships, a practice he warned has become the "acceptable face of unpaid labour in modern Britain" but should be banned.
The MP for Elmet and Rothwell told the Commons that "exploitation of a volunteer loophole" means some young people are not paid despite carrying out day-to-day tasks similar to part-time and full-time staff.
Mr Shelbrooke has developed draft legislation designed to extend the National Minimum Wage Act 1998 to cover those who carry out workplace internships.
It would ensure they are paid the minimum wage applicable to their age, meaning - at current rates - £4 an hour if under 18, £5.55 an hour if aged 18 to 20, £6.95 an hour if aged 21 to 24 and £7.20 an hour if 25 and over.
MPs heard the Bill would not affect those who donate their spare time to volunteer for charities, but will define those who undertake work and are paid a wage.
Mr Shelbrooke's National Minimum Wage (Workplace Internships) Bill is facing Tory opposition in the Commons, with concerns expressed about how it is drafted, which could prevent it from progressing.
It is also unlikely to become law without Government support.
Moving the second reading of his Private Member's Bill, Mr Shelbrooke said: "Unpaid internships are the acceptable face of unpaid labour in modern Britain today and should have no place in a meritocratic country that aims to work for the many and not the privileged few.
"This is a Bill to stop young people being exploited by those who gain from their unpaid endeavours.
"A Bill that sets about bringing an end to a new rise in the class society that means only those from a wealthy background can gain a privileged leg-up with an unpaid internship in their chosen profession.
"A Bill to level the playing field for many of my constituents in Elmet and Rothwell, who like many parents across this country cannot afford to pay for their child to work up to a year with no pay."
Mr Shelbrooke went on: "Let us look close to home as a starting point. A quick scan of the Work4MP website shows roughly 22 MPs advertising for unpaid interns outside of the politics and parliamentary study scheme.
"This breaks down to 13 Conservative MPs and nine Labour MPs, among other parties.
"Now, I make this point to show this is not a left-right argument, but a practice which takes place across this House.
"And it sends a message to businesses across the United Kingdom that exploiting the will of young workers is acceptable."
Tory Mark Pawsey (Rugby), intervening, asked: "What evidence do you have that employers and Members of Parliament as employers are seeking to flout the legislation?
"Isn't it the case that they're simply trying to give some valuable experience to young people at a sensible time in their lives?"
Mr Shelbrooke, in his reply, said: "A job is a job. And if work is adding towards an output then it should be paid for."
He added in his speech: "Many of the interns in this place, much like those working in private businesses, are undertaking day-to-day activities similar to those that many of us employ staff members to help us with in our offices.
"The fact of the matter is despite (Speaker John Bercow's) commendable efforts, working in Parliament has often been a matter of who you know, not what you know.
"If you're a young person eager to work here and with financial means to do so for free, then there are members who are taking on interns and refusing to pay at least the minimum wage for their labour."