However, the WPP results also showed that the UK is the slowest-growing region for the network.
Overall, WPP posted a reported revenue increase of 23 per cent to £1.35 billion, and a like-for-like revenue growth of almost 5 per cent, driven by improved organic growth over the past 18 months.
Omnicom's results, meanwhile, showed that the network increased its worldwide revenue by 7 per cent to £1.44 billion, the company's best organic revenue growth since the second quarter of 2001. Its domestic revenues increased by 9 per cent to £803 million.
Omnicom's ad revenue rose by more than 5 per cent, while customer relationship marketing grew by 10 per cent.
For WPP, every region posted double-digit growth, except for the UK, which has been hit by a lack of consumer confidence. UK revenues increased by 9 per cent.
The Asia-Pacific, Latin America, Africa and Middle East region showed the biggest increase with 26 per cent growth. Continental Europe grew by 19 per cent and North America by 17 per cent.
The WPP figures also show that like-for-like turnover in the UK grew by 1.9 per cent, compared with 5 per cent across the rest of the group.
The company, headed by its chief executive, Sir Martin Sorrell, said that it was on track to meet its full-year operating margin target of 14.5 per cent.