The boom in public sector job advertising may be slowing down, suggests a new survey.

An index of public sector job advertising, which tracks the number of public sector job advertisements in The Guardian newspaper, shows the number of vacancies down by 19% from its peak in mid-2003.

But public sector recruiters believe the decrease may be misleading, as more public sector bodies look to executive search and other methods to fill vacancies.

"The government has made it clear that the party’s over when it comes to public spending, so it’s inevitable there’ll be some slowdown," said Doug Bugie, chief executive of search firm Norman Broadbent.

"But [the research] is an imperfect indicator because it is only based on jobs advertised. Much of the work is invisible."

Economists also expect the share of public sector jobs to continue growing. City firm Lombard Street Research predicts that there could be twice as many jobs in government than in production industries by 2010.