The figures released by the Office for National Statistics (ONS) follows April’s IPA Bellwether Report, which revealed that event budgets had risen by 6.2% during the same period.
Rick Stainton, managing director at Smyle, said: "We are noticing better conversations with clients as briefs are more speculative and are supported by bigger budgets.
"Last year companies started to budget for an economic recovery and now the money is beginning to cascade down, with events seeing the positive effects of this. We have had a pharmaceutical client double its activity with us and the automotive sector is at a record high in the UK."
The figures mark the longest positive run of GDP growth since the financial crisis.
Jane Baker, commercial director, CWT Meetings & Events, said: "We are definitely seeing both an uplift in the number of events enquiries and the budget size. For March 2014, our venue-finding team have seen an increase in budgets of around 34% versus March 2013.
"We are expecting similar trends across our live events team where we are seeing a particular boost in the number of incentive event requests. Consumer confidence is definitely back and business confidence is following suit."
Head of project management at DRP Group, Nick Ruffles, said that as the economy picks up so too will costs: "Event budgets are going to have to increase because the cost of everything is going up.
"All sectors have realised that they have to take a different perspective than they had five years ago, but we are forecasting for a continued rise in budgets."
However, in the wake of an election and with interest rates likely to increase by 2015, issues on the horizon could dent future growth. Stainton added: "Confidence and nervousness is usually very mixed during an election as businesses are unsure how the Government’s economic strategy will fair.
"The ongoing situation in Ukraine could also dent confidence."