NEW YORK—Interpublic Group (IPG) PR firms have posted another strong quarter of growth, up by double-digits for the first three months of this year.

The organic increase is attributable to firms that are housed within IPG's CMG division, including Weber Shandwick, GolinHarris and DeVries. The same group of PR agencies were up in the 'high single digits' in 2013.

Overall, the CMG unit, which also features branding and experiential firms, was up 5.7% in the first quarter of the year.

Meanwhile, Omnicom's PR division, which includes FleishmanHillard, Ketchum and Porter Novelli, increased revenue by 1.2% on an organic basis during the quarter, to $325.4m. The PR agencies returned to growth after a Q4 decline in 2013, a year in which they grew by 1.5% overall.

Weber Shandwick CEO Andy Polansky told the Holmes Report that growth at his firm continued to outperform the market. Polansky pointed to digital investment as a key factor, alongside strong returns from corporate reputation, technology and healthcare.

Geographically, he added, North America and Asia-Pacific continued to lead the way, along with some European markets, notably the UK.

"I’m optimistic about the business overall given what we’re hearing from our clients," said Polansky. "We’re seeing it across the board. We have a couple of soft spots in Europe still but even there I feel like we have an important footprint and we serve a lot of multinationals. I don’t see a big drag."

Key recent wins for Weber Shandwick include Qualcomm, Microsoft China, Pearson and Abbott Labs.