Businesses should publish salaries in job adverts now, the prime minister is telling firms, rather than wait for a new law to come in that will force them to do so.
The government is planning to make pay details compulsory in adverts, with legislation on the issue being brought forward "as soon as possible".
It argues the change will help jobseekers, particularly those applying for their first job, and could help prevent pay discrimination. However, one industry group said setting pay was a complex process and regulating adverts was not always suitable.
It comes a week after the UK's equality watchdog said employees should legally be able to find out what their colleagues are earning.
The Cabinet Office launched a consultation into pay and reducing discrimination in the summer, and the government said there had been "overwhelming support" for greater transparency, with 94% of respondents backing the move.