Job vacancies have fallen to the lowest level in nearly four years, suggesting demand for workers is weakening as employment costs grow.

The number of jobs on offer fell to 781,000 in the first three months of the year, the Office for National Statistics (ONS) said, while payroll numbers also declined.

Average UK pay continued to rise - up 5.9% - but increases in employer National Insurance Contributions as well as National Minimum Wage hikes which came into force this month are forecast to weigh on salaries.

The UK unemployment rate remained at 4.4%, roughly the same as the previous three months.

The employment rate for people aged 16 to 64 years was 75.1%, still below Labour's target of 80% employment.

However, the ONS has said its jobs figures should be treated with caution because of low response rates to its employment survey, on which the figures are based.

Jane Gratton, deputy director public policy at the British Chambers of Commerce, said: "The labour market continues to be a significant pressure bearing down on businesses of all sizes.

"The rising cost of employment is a major challenge for employers. While wage growth has eased once again, it continues to significantly outpace inflation. Added to this, the employer national insurance hike this month has ramped up staffing costs. It will be some time before we will fully understand the true impact of these increases on jobs, investment, and the extent to which firms can absorb and adjust to the rising costs.

"Vacancies have fallen on the quarter, underlining our latest research which shows workforces aren't growing. Recruitment remains a huge challenge and labour costs are forcing businesses to put up their prices."

She added: "The government must ease the cost pressures on businesses, so they have the freedom to recruit and invest in a skilled workforce. The recent announcement on construction training investment by the Chancellor was welcome. However, more flexibility in the skills system is needed to boost training and development across the economy. "