The declaration emerged from attempts by publishers in Germany to have copyright law there changed to better protect newspaper publishers.
The Hamburg declaration stops short of calling for new rights but did say that it welcomed "the growing resolve of federal and state governments all over the world to continue to support the protection of the rights of authors, publishers and broadcasters on the internet".
The declaration claims that the business of publishing is no longer secure because of the digital distribution of its works.
"The internet offers immense opportunities to professional journalism – but only if the basis for profitability remains secure throughout the digital channels of distribution. This is currently not the case," it said. "Numerous providers are using the work of authors, publishers and broadcasters without paying for it. Over the long term, this threatens the production of high-quality content and the existence of independent journalism."
"For this reason, we advocate strongly urgent improvements in the protection of intellectual property on the internet," it said.
The publishers have not specified exactly what improvements they want to the way that intellectual property law deals with newspaper content. The German movement out of which the declaration grew had sought a right which gave them greater control over secondary use of their work.
Newspapers have long published their material online but have failed to generate enough revenue from that activity to offset falling physical sales and advertising.
Some have objected to aggregation by the likes of Google's News service, which publishes headlines and snippets of stories and links to newspapers' own sites for the stories themselves.
Publishers in Belgium have won a court victory against Google through their representative body Copiepresse, which successfully argued in a Belgian court that the service's caching of its members' material was copyright infringement.
The two parties later came to a partial compromise that allowed Google to include the newspapers in its search engine but not its news service.
News agency Associated Press announced earlier this year that it would begin to take legal action against any company that republished its works without permission or without sharing revenues.
Newspaper publishers could have their material removed from Google News and other services at a stroke by including on their web pages a small piece of code which would instruct these services to ignore the pages.
Publishers, though, want the attention that Google and other services bring, but also want a greater say in how their material is used. The EPC and WAN have developed a system which they want publishers and aggregators to use to communicate more complex copyright terms and conditions.
Called Automated Content Access Protocol (ACAP), it is designed as an alternative to the long-established signals which simply tell search engines to scan a site or not scan it.
"We continue to attract ever greater audiences for our content but, unlike in the print or TV business models, we are not the ones making the money out of our content. This is unsustainable," said Gavin O'Reilly, chief executive of Irish newspaper publisher Independent News and Media and president of WAN. "Publishers failing will benefit no-one, least of all consumers, or indeed the search engines and other aggregators who currently make huge profits on the back of our intellectual property".
"We need search engines to recognize ACAP as a step towards acknowledging that content providers have the right to decide what happens to their content and on what terms," said O'Reilly. "The European Commission and other legislators call on our industry constantly to come up with solutions – here we have one and we call upon the regulators to back it up."