A record 5 million UK workers were now in low-paid jobs, research from a think tank points out.
The number of people earning under two-thirds of average hourly pay - equivalent to £7.69 an hour - rose by 250,000 to 5.2 million last year, according to the Resolution Foundation.
It added a "growing rump" of low-paid jobs posed a problem for ministers as it kept tax revenues low.
According to the government, it had taken lower earners out of income tax and wanted to increase the value of the minimum wage.
Workers in the UK were more likely to be low paid than workers in comparable economies like Germany and Australia, according to report of the left-of-centre think tank.
London, Glasgow and Belfast last week witnessed protests by tens of thousands of people over pay and austerity measures.
Teachers, nurses and civil servants were among those opposing a below-inflation 1 per cent pay offer from the government.
According to the report there was a serious problem of people being stuck in low-paid jobs, and almost one in four minimum wage employees continued on that rate for the last five years.
According to the Foundation the increase in the number of low paid workers partly reflected growth in employment, but there was also a reverse in the previous year's slight fall in low-paid work.
The think tank's chief economist, Matthew Whittaker, said, "While recent months have brought much welcome news on the number of people moving into employment, the squeeze on real earnings continues. While low pay is likely to be better than no pay at all, it's troubling that the number of low-paid workers across Britain reached a record high last year.
"All political parties have expressed an ambition to tackle low pay. Yet the proportion of low-paid workers has barely moved in the last 20 years. A focus on raising the minimum wage can certainly help the very lowest paid workers in Britain, but we need a broader low-pay strategy in order to lift larger numbers out of working poverty.
"Economic growth alone won't solve our low-pay problem. We need to look more closely at the kind of jobs being created, the industries that are growing and the ability of people to move from one job or sector to the other, if we're really going to get to grips with low pay in Britain today."