The World Federation of Advertisers survey of 34 major advertisers with a collective $59bn (£45bn) outlay on global media and marketing found that 65% plan to increase spend on influencer-marketing.
It found that 71% of respondents said the way their brand’s relationship with an influencer is disclosed to consumers was an "absolutely essential" or "very important" part of the process of selecting influencers.
However, 4% said it was not important at all. In addition, a substanial minority revealed that the influencers their brand works with do not disclose the relationship; 8% said this was "always" the case and 8% said this was "very often" the case.
The findings come in the wake of various controversies over transparency around influencer marketing in the UK, where a recent nationwide poll found that people believe they are unregulated, despite being within the remit of the Advertising Standards Authority.
Outside the UK, Pewdiepie last year received accusations of anti-Semitism, and Logan Paul faced a backlash after filming, editing, and posting a vlog of himself and others touring Japan's infamous "Suicide Forest," where they found the corpse of a suicide victim.
The WFA polled its members in order to inform its future best-practice guidance for brands working with influencers.
Rob Dreblow, global head of marketing services at the WFA, said: "All the brands participating comply with the differing regulations in all the markets where they operate but it’s clear there’s room for improvement and the guidance will look to encourage best practice and provide help on how to do this.
"Marketers tend to instinctively prioritise effectiveness. The vast majority understand how essential disclosure is but this shows that there are still some companies where the message needs to get through. That's why our guidance document should help to address this deficit."
The ways in which influencers do disclose they have a relationship with a respondent’s brand include hashtags (used always or very often according to 68% of respondents), descriptions in the post/video (63%), paid partnership labels (43%) or a verbal mention (50%).
The survey also found 64% of respondents use external partners to find relevant influencers and 63% use them to manage the partnership.
The WFA said it would work on developing the guidance with members such as Unilever, whose chief marketing officer Keith Weed took a stand on transparency last month by pledging not to work with influencers who buy followers or use bots to amplify their reach.
The survey unsurprisingly found that quality of followers was "absolutely essential" or "very important" for 96% of respondents. Similarly, the credibility and reputation of the influencer was also critical for the vast majority, scoring 93% on the same measure.
Loerke added: "Influencer marketing is becoming a key channel for many marketers but it will only be effective if consumers can trust the influencers by declaring paid relationships and marketers can trust that they are reaching real people not bots.
"This area has evolved rapidly and this research provides a benchmark revealing how marketing teams and their external partners are managing the new channel."
Yet to receive the results you’d like from your influencer marketing efforts? Learn how to choose the right influencers, create and maintain long-lasting relationships and discover best practice for measuring campaign success at PRWeek’s Influencer Breakfast Briefing this November.