At least 1.4 million employees in the UK are on zero hours contracts, the latest figures from the Office for National Statistics (ONS) show.
More than one in five health and social work employers reported using them. And larger employers were more likely to use them than smaller employers.
Just 12% of businesses with fewer than 20 employees use zero hours contracts, the first employer-based survey for the ONS shows.
There was also evidence of 1.3 million additional contracts where no work was undertaken over the two-week survey period.
Last year a compete ban on the contracts was ruled out by Business Secretary Vince Cable, because they offer "flexibility" to employers.
However, following the release of the figures he told the BBC: "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.
"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."
Labour leader Ed Miliband said that he would crack down on zero hours contracts if his party wins the 2015 general election.