Employers could be banned from preventing staff on zero-hours contracts from working elsewhere as part of a crackdown on abuse of the controversial deals, Vince Cable will announce on Wednesday.

A government consultation on zero-hours contracts, designed to prevent misuse by employers, will seek views on whether legislation should be introduced to ban so-called "exclusivity clauses".

Cable will say: "We don't think that people should be tied exclusively to one employer if it unfairly stops them from boosting their income when they are not getting enough work to earn a living.

"We also want to give employees and employers more guidance and advice on these types of employment contracts.

"Employers need flexible workforces and people should have the choice in how they work. But this shouldn't be at the expense of fairness and transparency."

The business secretary announced in his speech to the Liberal Democrat conference in September that he would act against "abusive practices in zero-hours contracts". He highlighted the unfairness of "exclusivity arrangements which prevent workers seeking alternatives, even when they are given no work".

Cable will say that he has no plans to ban zero-hours contracts, which can offer flexibility for some employees who have to look after children or people who want to top up monthly earnings. "We believe they have a place in today's labour market and are not proposing to ban them outright, but we also want to make sure that people are getting a fair deal," he said.

But he will say that research over the summer has highlighted the need to tackle abuses and to improve transparency. He believes there is no clear legal definition of zero-hours contracts which can lead to confusion.

Employers welcomed the government's support for such contracts if introduced on a fair basis. Alexander Ehmann, of the Institute of Directors, said: "The IoD is pleased that the government has recognised the important contribution that zero-hours contracts have made in keeping people in employment and offering flexible ways for employers to manage fluctuations in demand.

"This consultation underlines how important a varied and flexible labour market is to our economy, and quite how out of touch those arguing for an indiscriminate ban on this casual form of work were."

But Frances O'Grady, the TUC general secretary, said: "The growth of zero-hours contracts is one of the reasons why so many hard-working people are fearful for their jobs and struggling to make ends meet, in spite of the recovery.

"But while the government has identified some of the problems faced by those with zero job security, it's desperately short on solutions to curb the use of these contracts.

"Through the consultation, the TUC and unions will propose tougher action in order to tackle abuse of zero-hours contracts, which can leave people not knowing how much they'll be earning from one week to the next."