Companies cut back on hiring even before the outcome of the EU referendum, according to a new report.
A study by jobs site Adzuna found that advertised vacancies fell by 0.6% in May, the second consecutive monthly drop.
Uncertainty about the referendum result led to employers being "cautious", leading to a temporary hiring halt, said the report.
Advertised salaries fell by 1.2% last month to £33,000, the biggest monthly fall in almost two years, said Adzuna.
Co-founder Doug Monro said: "May marked a nervous month for employers. It's hard to imagine life after the Brexit debate but companies need to adapt quickly to this leap into the unknown.
"Thankfully, short-term volatility shouldn't cause lasting damage to job prospects. We have a strong and open economy, which has led the tech sector to thrive.
"It's crucial to keep up our relationship and trade with European countries, and others, to drive growth and momentum.
"Hiring has been particularly hurt by uncertainty in the run-up to the vote, as senior workers rode out the political storm before hopping companies. Lower-paid roles, such as temporary summer jobs, have been less impacted."