Israel and the Palestinian Authority compromised in the name of nature this week, teaming up at the last moment to back the Dead Sea in a contest to chose the world's top seven natural wonders.

Just days before the contest rules would have forced the Dead Sea's elimination, Israel's ministry of tourism took over as official sponsor from the Megilot Dead Sea Council, removing a big political obstacle blocking Palestinian participation.

The famously buoyant Dead Sea, the world's most saline lake, lies at the bottom of the Jordan Rift Valley at the lowest spot on earth, some 400 metres below sea level.

The Palestinians had refused to form a sponsorship committee because Israel's Megilot municipality covers occupied West Bank land, including Jewish settlements near the Dead Sea which it considers illegal.

This made it impossible to meet the rules of the New Seven Wonders of Nature Internet vote, which stipulate that a nominee "located in more than one country" must be backed by all.

For the Dead Sea, Israel, Jordan and Palestinian sponsorship committees were a pre-requisite for continuing in the contest. A red light has flashed for months on its entry on the New7Wonders website, warning the nomination was not complete.

But on Thursday, Ahmad Salami of the Palestinian foreign ministry told Reuters President Mahmoud Abbas had given instructions to back the Dead Sea in the competition.

Foreign Minister Riyad al-Malki also instructed Palestinian diplomatic missions abroad "to promote this historic and human milestone and to issue booklets to educate people about the Dead Sea" and the need to preserve it.

It was a small triumph of common interest over one of the many red lines in the intractable Israeli-Palestinian conflict.

Organisers were "delighted that dialogue and a recognition of mutual interest has transcended politics in the best interest of the Dead Sea - and of the millions eagerly participating worldwide," said New7Wonders spokeswoman Tia Viering.

"The Dead Sea's participation in the New7Wonders of Nature campaign has been salvaged at the very last minute. We know that many N7W fans will be happy for the chance to vote for this unique, endangered natural treasure."

The next round of voting on July 7 will narrow the field to 77 from 261, over 7 nature categories including forests, mountains, lakes and rivers.

The Dead Sea has been shrinking dramatically for the past 30 years. About 90 percent of feed-waters from the Jordan River are now diverted for human use, and the sea is further depleted by chemical and mineral extraction industry. Supporters of the New7Wonders contest say the 7 winners, to be chosen by global Internet vote in 2011, will enjoy a public relations boost likely to increase tourism, as it did for Jordan when the ancient ruins at Petra were chosen one of the 7 new, man-made wonders in 2007.

N7W says 100 million people voted in that contest and it predicts many more will participate in the "nature" final.