Media playback is unsupported on your device Media caption Dale King: "If work is slow, then the amount of money I earn that week may not be sufficient to cover the bills"

Nearly half of big companies in the UK use a total of 1.4 million zero-hours contracts, a study from the Office for National Statistics (ONS) says.

Zero-hours contracts do not guarantee a minimum number of hours of employment.

The ONS recently estimated that 583,000 people, around 2% of the UK workforce, were employed on zero-hours contracts between October and December 2013.

It said the data suggested that most workers on such contracts had at least two jobs.

One in five employers has at least one employee on a zero-hours contract

Staff have no guaranteed hours

They are entitled to holiday pay

The contracts are often used in retail and in the hospitality sector What are zero-hours contracts?

Last year, Business Secretary Vince Cable ruled out a complete ban on the contracts, because they offer employers "welcome flexibility".

Following the release of the ONS figures Mr Cable said it was also clear there had been some abuse of those on zero hour contracts by some less scrupulous employers.

"Given the current estimates of people on these types of contracts, it is important we take action. That is why I launched a consultation on the issue of exclusivity in zero hours to ensure people are getting a fair deal," he said.

"Students, older people and people wanting to top up their income want to work flexibly, but we want to make sure they understand their rights and that they are not tied exclusively to one employer.

"We will be publishing the results of this consultation shortly."

Last week, Labour leader Ed Miliband said zero hours contracts had "spread like an epidemic" as he promised to crack down on them if his party wins the 2015 general election.

The study found that more than 20% of health and social workers are employed on a zero-hours contacts.

Media playback is unsupported on your device Media caption Hannah Reed from the TUC: "These are shocking figures and that show millions of people in Britain are trapped in insecure jobs"

But zero-hours contracts are rare in financial services, the ONS found.

People with zero-hours contracts were disproportionately students, female and under 25 or over 65, the study also found.

"These patterns may partly reflect the groups most likely to find the flexibility of 'zero-hours contracts' an advantage," the ONS said.

The Trades Union Congress (TUC) said the figures showed the UK jobs market was far more unstable than the government suggested, and urged ministers to crack down on the "abuse" of zero-hours contracts by employers.

"Insecure work with no guarantee of regular paid hours is no longer confined to the fringes of the jobs market," said Frances O'Grady, the TUC's general secretary.

"It is worrying that so many young people are trapped on zero-hours contracts, which can hold back their careers and make it harder to pay off debts like student loans.

"The fact that these contracts have become the norm in tourism, catering and food will be a major concern for the millions of people employed in these industries."

More research

ONS said it found evidence of a further 1.3 million contracts where no work was undertaken.

It said the total might include:

people with contracts with several employers

agency staff

those not wanting to work

those who had found another job elsewhere, but remained on employer records

people on leave or sick

and those not offered work during the period of the study

It added some of contracts "probably" needed to be added to the official 1.4 million estimate, but that it wanted to investigate in more detail.

The ONS said it would carry out further research and report later in 2014.

The Chartered Institute of Personnel and Development, Britain's main human resources body, estimated last year that employers used about one million zero-hours contracts.