Tens of thousands of tourists, scientists and amateur astronomers from around the world are waiting anxiously across tropical northern Australia to find out whether the clouds will part in time to see a total eclipse of the sun.

Forecasters have predicted cloudy skies for dawn on Wednesday local time, when the Moon will pass between the Sun and Earth and plunge part of the continent's north-east into darkness.

"There will be breaks [in the clouds] but it's just a matter of the luck of the draw whether you get a break at the right time," said Andrew Mostyn, a Bureau of Meteorology forecaster in the state of Queensland. "It's a bit of bad luck."

The eclipse will cast its 95-mile (150km) wide shadow starting at dawn in Australia's Northern Territory, then cross the north-east tip of the country before swooping east across the South Pacific, where no islands are in its direct path. A partial eclipse will be visible from east Indonesia, the eastern half of Australia, New Zealand, Papua New Guinea and southern parts of Chile and Argentina. Totality – the darkness that happens at the peak of the eclipse – will last just over two minutes.

US astronomer Jay Pasachoff, who travelled to Australia in hopes of viewing his 56th solar eclipse along with a team of about 50 scientists and students who have fanned out across the region, said he would not have missed it whatever the weather forecast.

"Just imagine you were a heart surgeon and someone actually told you you could look inside a human heart only for two minutes, and only if you went halfway around the world," he said. "You would do it."

Some Queensland hotels have been booked up for more than three years and more than 50,000 people had flooded into the region, said Jeff Gillies, regional director of Queensland Tourism. Preferred viewing platforms included beaches, boats, fields and hot air balloons.

Scientists will be studying how animals respond to the eclipse, with underwater cameras capturing the effects of sudden darkness on the creatures of the Great Barrier Reef.

The last total solar eclipse visible in Australia was 10 years ago, in the South Australian outback.