Authorities in several Papua New Guinea maritime provinces are searching for people missing at sea in relation to a number of separate cases of reported boating mishaps in the past week.

PNG authorities managing separate cases of missing people

New Ireland, Milne Bay and Bougainville are each managing cases where people on small boats are missing, or in some cases where their bodies have been found.

And the big case which has been gripping the nation, a boat journey in East New Britain province that turned to tragedy, remains the subject of widespread search efforts.

East New Britain disaster officials continue to search for up to 27 people missing since last Saturday, 18 July, after their two boats capsized while travelling from the Duke of York group to Kokopo.

According to the provincial administrator Levi Mano, as of Monday afternoon, they had found 13 bodies.

"They've all been found in New Ireland province, around Djaul and Tigak islands," he said, in reference to an area hundreds of kilometres off course from the group's planned journey.

Two people from the group made it to land, near Rabaul, later on the same day the two small boats capsized.

They have help people onshore piece together what happened - when one of the boats capsized in rough seas, the other boat tried to rescue them, but that boat became overwhelmed with too many people and soon capsized too.

Mano said people in his province are devastated, shocked and grieving over the disaster, which involved up to 17 children.

He said the disaster committee's plan was to continue searching for the remaining bodies to ensure they were returned to their families in a dignified manner.

Dangerous conditions for sea travel

Mano said the incident happened in St George Channel, which can turn dangerous quickly.

"They drifted quite a bit of distance," Mano said, adding that New Ireland authorities had been working tirelessly with East New Britain counterparts to search for, and retrieve the bodies.

However, in another incident off New Ireland's north, a search was underway on Friday for six people missing after their boat capsized, leaving the local disaster officers overwhelmed.

In another part of the Niugini Islands region, Bougainville, authorities told RNZ Pacific on Monday that they were still searching for three people missing in small vessel that departed Nissan Island bound for Buka on Saturday, 18 July.

Meanwhile, in Milne Bay, local media is reporting that at least three people ave died, and up to four others are missing, after a passenger dinghy capsized during a perilous journey in severe weather conditions on Thursday afternoon, 23 July, not far from the mainland coast

Mano said the kind of weather that the wider region is experiencing - including sustained strong winds likely due to the El Nino phase - must be taken seriously by people travelling by sea.