Demand for temporary staff has increased at the fastest pace since October 2018, according to new research.
There was a bigger increase in vacancies for temporary workers in December than for permanent jobs, according to the Recruitment and Employment Confederation (REC) and KPMG.
The research, which draws on data from 400 UK recruitment and employment consultancies, found firms were concentrating on temporary workers due to uncertainty over the coronavirus pandemic and Brexit.
KPMG vice chairman James Stewart said: "The emergence of a vaccine did bring more confidence to the jobs market in December, with a small increase in permanent appointments.
"Temporary billings were also sharply up across the UK, although London was a notable exception."
Vacancies for permanent workers also rose, but only marginally. Also, pay for permanent and temporary workers rose for the first time since March, albeit at mild rates.
Neil Carberry, chief executive of the REC, said: "The important thing now is to maintain as much of that momentum as possible through the new lockdown.
"With business cash flows under renewed pressure, helping employers protect and create jobs is essential. We need a long-term plan to support businesses across the supply chain - not just those required to close.
"Regions have been recovering at different speeds and London continues to lag behind. London is home to some of the most deprived boroughs in the country, so this is particularly worrying."