Google's acquisition of YouTube provides a "tantalizing opportunity" for the search giant to boost its advertising model, but the success of the partnership is far from certain, according to Gartner.

Analysts at the research firm said Google could struggle to maintain YouTube's loyal following and attract advertisers, highlighting the copyright concerns faced by the video-sharing site.

"Brand advertisers, in the main, are unwilling to place their marketing messages alongside (or in some cases inside) stolen or controversial material," said Gartner. "YouTube claims to be poised to deploy technology that roots out copyrighted material. But such efforts have been largely unsuccessful."

Gartner said YouTube's efforts to stamp out copyright infringement on its network had been marred by both false positives -- where legitimate content is deemed to by copyrighted -- and "significant violations that slip through the cracks".

That means the companies face "the burden of proving to advertisers that they will be able to resolve this issue without alienating their audience," the research firm added.

Google announced its US$1.6 billion acquisition of YouTube last week, but partners such as News Corp and content owners including Time Warner have already expressed their concern about the implications of the deal.