The number of jobs on offer in the UK fell to 781,000 in the first three months of the year, according to the latest data from the Office for National Statistics (ONS).
Some experts believe the rising cost of employing people is making businesses hold back on hiring new staff.
In April the rate of employer National Insurance contributions (NICs) went up and so did minimum wages across different age groups.
Business groups have also called for urgent changes to the forthcoming Employment Rights Bill over concerns it could hit hiring.
Under the new law being scrutinised in the House of Lords on Tuesday, company bosses will be required to offer a zero-hours worker a guaranteed-hours contract based on the hours they clock up during a 12-week period.
The biggest concern among retail HR directors is that this risks making it much harder to offer people part-time jobs, according to a BRC survey.
It surveyed HR directors at 30 businesses, together employing 585,000 retail workers.
Just over half said the law change would result in a reduction in staff numbers in their business, while 61% said the new law would reduce flexibility in job offerings.