It comes as the Recruitment & Employment Confederation's (REC) monthly report showed permanent jobs and accompanying starting salaries grew at the quickest pace in three months in February. Meanwhile, demand for permanent staff saw its sharpest increase in six months.
"The UK labour market is at a critical juncture," Kevin Green, chief executive of REC, said.
"Permanent hiring improved last month, demand for staff remains strong, and pay is going in the right direction - but serious threats are looming just around the corner."
The availability of staff for both permanent and temporary and roles continued to fall last month, the report showed. However, rates of decline did ease to the slowest in at least two years.
But REC warned chancellor George Osborne against making it harder for businesses to hire skilled workers in his Budget next week.
“Next week the Chancellor will announce his plans for the coming financial year, at a time when recruiters across the country are reporting serious skills shortages alongside buoyant jobs growth. Now is not the time to put up additional hurdles that could throw the jobs-rich recovery off course," Greens said.
Similarly, it flagged the in/out EU referendum, which will take place on 23 June, as another potential sore spot.
"The EU referendum carries a very real risk that business confidence will be curtailed and investment in hiring could falter. It’s vital that we have an informed debate about the impact the referendum might have on jobs, both in the short and long term."
“Global economic headwinds only add to the uncertainty around what the months ahead hold."