An Indonesian search and rescue team is searching for seven people, including four Australian tourists, reported missing in the waters of Aceh following bad weather. The group was in a wooden speedboat in the waters around Sarang Alu and Banyak islands in Aceh Singkil district.

The Department of Foreign Affairs and Trade confirmed the four Australians are Elliot Foote, Steph Weisse, Will Teagle, and Jordan Short. The families of the group said that their hearts "are aching at the thought" the four of them were missing at sea.

"We continue to pray and hold out hope they will be found," the families said in a statement. "We'd like to thank the Indonesian authorities and the Australian Government for their ongoing assistance while search and rescue efforts continue.

"We ask that the media respect the privacy of our family and friends during this distressing time."

Elliot Foote and Steph Weisse are among the missing (Instagram)

It is understood the group were on their way to the Banyak Islands.

Julian Lauencoan, the owner of Banyak Surf Resort, a different resort to which the missing boat was going, joined efforts to locate the missing boat alongside two other rescue vessels and a helicopter.

He told the ABC that conditions on the water have improved from Sunday night, and that he and his crew plan to go out again in the morning in waters where sharks are not a major concern.

"There's some wind but it's nothing crazy like last night. It's much better — not blue skies — but still windy and difficult to drive against the wind."

Mr Lauencoan said he believes that the missing wooden boat is unlikely to sink, and given the direction of the winds, those aboard won't have been blown out to sea.

"The wind was not easterly, which would push it to the Indian Ocean, but would instead push it west back to land," he said.

"It can happen: I have heard a couple of stories like this where they would spend a few days at sea, but once they come close to land fishermen find them."

"They have water and food on the boat, so they'll be okay for a few days."

Those missing were part of a group of 12 Australian nationals and five Indonesians who were travelling to Pinang Island in two boats.

The boats left North Nias port in Nias island — which is located around 150 kilometres from Indonesia's Sumatra island — on Sunday afternoon and experienced bad weather with very heavy rain during the trip. Ten of them earlier decided to stay and shelter on Sarang Alu island, while the others continued the trip, a written statement from Nias Search and Rescue Agency said.

The resort on Pinang Island later reported to the agency that the boat with 10 passengers had safely arrived, but the boat carrying the seven that had left earlier had not been seen.

DFAT said it was working closely with Indonesian authorities to support search and rescue efforts. The department was also providing consular assistance to the four families, a spokesperson said in a statement.

"Our thoughts are with the family and friends of those missing during this distressing time," the statement said.

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