In April 2013 public sector pay was between 2.2% and 3.1% higher than the private sector. This is down significantly from 2010, when the difference was more than 4%. The report suggests that restraints on budgets in the public sector have contributed to the trend.
Jamie Jenkins, labour market analyst at the ONS, told HR magazine there are several reasons for higher pay in the public sector.
"Public sector workers tend to be older. With age comes higher pay," he said. "They are also generally better qualified. The narrowing of the gap started in about 2010 when we saw all the freezes in pay for public sector workers."
The area of the UK with the highest difference in pay is Northern Ireland. Public sector workers in Northern Ireland earn 15% more than those in the private sector. The private sector is the strongest in London, where employees earn, on average, 8% more than public sector staff.
The private sector has slightly fewer part-time workers than the public. While 74% of workers in the private sector have full-time roles, it is only 68% in the public sector. This leads to average hours being worked in the public sector being slightly lower, at 30.2 compared to 32.7.
Women are more likely to be in highly-skilled positions in the public sector, according to the report. Almost half (42%) are in positions classed as 'high skilled', but in the private sector this drops to just 16%. Most women (54%) in the private sector are in roles classed as 'lower middle skill'.
The report also shows that workers in the public sector generally have higher academic qualifications. When looking at the highest qualification held, 45% of public sector workers hold a degree or equivalent, compared to 27% in the private sector.