A search party was combing the seas for the five tourists and two instructors -- all women -- who went missing during their third dive near the islands of Nusa Lembongan and Nusa Penida southeast of Bali on Friday afternoon, deputy consul general of Japan in Bali Yasue Katsunobu said.

Their boat's skipper called the police after the women did not resurface, Katsunobu said, adding the boat was hired from Yellow Scuba on the beachside strip of Sanur.

"We are still searching for the seven missing divers. So far there's no indication of where they are," Katsunobu told AFP on Sunday.

A staff member for Bali's search and rescue agency said a around 100 people had joined the operation from his agency, the maritime police, the navy, as well as fishermen, and Japanese and Indonesian diving instructors.

"After having no luck on Saturday, we have expanded the search area," Amtarama, a Bali search and rescue official who goes by one name, told AFP.

"We have seven official boats, not including the fishermen's, and a helicopter has been scanning the waters since the early morning," he said.

The team will continue until dark, he said, adding that weather conditions had so far been fine.

Rescuers searched until 3pm on Saturday when bad weather, including heavy rain, forced them to halt the mission, officials said.

Police said earlier that the women had left from Crystal Bay on the larger island Nusa Penida when they went missing.

- Popular dive site -

Crystal Bay is a popular site for seeing Nusa Penida's famous mola-mola, or ocean sunfish, and is recommended for experienced divers because of its strong downward current.

The bay was closed temporarily in August 2012 after a Danish man and Japanese woman died diving in the same week, according to reports.

The skipper said that he was following the divers for some 20 minutes before a sudden downpour of rain made the water cloudy, according to a report in Japan's Asahi Shimbun newspaper.

He moved his 10-metre-long boat to a point some hundreds of metres away where the divers were expected to resurface at an agreed time, the report said.

The skipper said he searched for them for an hour before reporting the incident.

"I've been guiding since 2009, and I've been to the area (of the accident) many times. Why did this happen?" he said in the report.

Katsunobu said that the seven women were very experienced scuba divers with at least 50 dives each under their belts.

Japan's Kyodo news agency said the missing women were named by police and rescue authorities as: Ritsuko Miyata, 59, Emi Yamamoto, 33, Nahomi Tomita, 28, Aya Morizono, 27, Atsumi Yoshinobe, 29, Shoko Takahashi, 29, and Saori Furukawa, 27.

Bali is often pounded by heavy afternoon rain during the wet season, which lasts around six months of the year.

Nusa Lembongan and Nusa Penida are popular scuba diving spots and are part of the Coral Triangle, widely considered the world's richest underwater wilderness.

The Coral Triangle includes the waters of six nations in the Indian and Pacific oceans -- Indonesia, Malaysia, the Philippines, East Timor, Papua New Guinea and the Solomon Islands.