Industry sources said this is partly due to greater pressure being exerted by agency groups on media owners for better rates to meet terms agreed in client pitches.
Reckitt Benckiser, which pitched its £84m media business last year before appointing ZenithOptimedia, is not trading with Channel 4 and is said to have issues with Sky Media as it looks for greater value in the TV market.
Consequently, ads for brands including Nurofen, Vanish, Air Wick and Clearasil are not running on C4 and the majority of Sky channels.
Aegis Media, whose clients include Coca-Cola, is in dispute with Five and ads from
its clients are not running on the broadcaster's channels. However, Five is benefiting from Reckitt's dispute with the other channels.
Unilever's stand-off with Sky Media, reported by Campaign in January, also continues. Campaigns from the FMCG giant are not running on Sky channels after the broadcaster and Unilever's agency Mindshare, which recently retained the Unilever account following a pitch, were unable to agree terms.
Such stand-offs are often resolved earlier in the year following a trading season. One broadcast source said agency groups could face difficulties as they look for greater value in a TV market where inflation is becoming a factor.
Channel 4, Five and Sky Media declined to comment.