Relief workers tried desperately on Tuesday to reach Vanuatu's remote outer islands that were smashed by a fierce cyclone, as an Australian official reported scenes of widespread destruction.

Radio and telephone communications with the South Pacific nation's hard-hit outer islands were just beginning to be restored, but remained incredibly patchy three days after what the country's president called a "monster" storm.

Australian military planes that conducted aerial assessments of the outer islands found significant damage, particularly on Tanna Island, where it appears that more than 80 percent of homes and other buildings were partially or completely destroyed, Foreign Minister Julie Bishop said.

"We understand that the reconnaissance imagery shows widespread devastation," Bishop said. "Not only buildings flattened palm plantations, trees. It's quite a devastating sight."

The U.N. Office for the Coordination of Humanitarian Affairs reported that 11 people were confirmed dead, including five on Tanna Island, downgrading their earlier report of 24 casualties after realizing some of the victims had been counted twice. Officials with the National Disaster Management Office said they had no accurate figures on how many were dead, and aid agencies reported varying numbers.

The confusion over the number killed reflects the difficulty officials face as they try to deal with a disaster spread across many remote islands with a near-total communications blackout.

Relief workers have been battling poor weather and communications issues for days, hampering much of their efforts to reach the outer islands. A break in the weather on Tuesday gave them a chance to try again, though access remained difficult. Most of the islands have no airports and those that do have only small landing strips that are tricky for large supply planes to navigate.

"There are over 80 islands that make up Vanuatu and on a good, sunny day outside of cyclone season it's difficult to get to many of them," said Colin Collett Van Rooyen, Vanuatu director for Oxfam. "Until today, the weather has been particularly cloudy, so even the surveillance flights would have had some difficulty picking up good imagery."

Teams of aid workers and government officials were planning to fly to the southern islands, which suffered a direct hit from the storm. The teams were expected to meet with local disaster officials and conduct damage assessments, said Sebastian Rhodes Stampa, disaster coordinator for the U.N.'s humanitarian affairs office.

Some of the islands were just beginning to get their phone networks running again, and technical crews were en route to set up data and voice satellite communications. Officials hoped to restore communications to the islands within 48 hours, Stampa said.

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Relief Teams Head to Vanuatu's Cyclone-Hit Outer Islands