Update March 31 :
The article below comes from the Papua New Guinean newspaper “The National“

Update 09:16 UTC : The tsunami threat was inflicted by the type of earthquake, a mainly thrust mechanism who is responsible for an upwards movement of the water column on top of the epicenter ( “Understanding Beach Balls” article)

Update 03:30 UTC : TSUNAMI THREAT LARGELY OVER

Update 01:51 UTC : USGS has recalculates its data and now reports a Magnitude of 7.5 at a depth of 40 km

Update 01:40 UTC : Tsunami Message nr. 3 from the PTWC (almost no change)

Update 01:33 UTC : Robert Speta, meteorologist at NHK Tokyo did send the following tweet, which is in part hopeful but at the downside we do not like to see the word damage.

Update 01:25 UTC : Dr. James Daniell from CEDIM, Karlsruhe, Germany has put all data in his model and is getting a chance of 0 to 2 fatalities and 0 to 10 injuries.

Update 01:20 UTC : 3 buoys (the biggest yellow diamonds) are currently blinking which means that they have detected a change in level (tide omitted)

Update 01:15 UTC : New version of the GDACS Tsunami waves expectation list (the full list can be consulted here)  :

Update 01:01 UTC : Professor Max Wyss, specialized in computing human impact has published his report and he expects  0 to 20 fatalities and 20 to 200 injured. We at Earthquake-report.com do expect, based on the current parameters, that there is only a small chance for injuries. PNG is however a nation who has not a good reputation in listing the exact number of injured as most of the country is not accessible by road.

Update 00:59 UTC : PNG is used to strong swaying and massive earthquakes. The biggest treat is however tsunamis but people living in coastal areas are also used to auto-evacuate immediately after they feel strong shaking. Tsunami waves can however inflict serious damage along the coasts.

Update 00:50 UTC : GDACS has issued a list of theoretical tsunami heights. The main treat area are the closest coasts of New Britain and New Ireland. The depth of the hypocenter is an important factor for the calculation of the wave height.

IMPORTANT UPDATE 00:37 UTC : PLEASE READ THIS MESSAGE CAREFULLY IF YOU LIVE ON THE COASTS OF THE FOLLOWING ISLANDS

Update 00:31 UTC : Damage is possible but as people are used to very strong earthquakes on PNG and as the epicenter if below the ocean we expect only limited damage. We are more concerned about the tsunami treat.

Update 00:17 UTC : Official Tsunami message from the PWTC : HAZARDOUS TSUNAMI WAVES FROM THIS EARTHQUAKE ARE POSSIBLE
    WITHIN 1000 KM OF THE EPICENTER ALONG THE COASTS OF PAPUA NEW GUINEA AND SOLOMON ISLANDS

Update 00:14 UTC : Very strong shaking expected in a wide radius. Due to the hypocenter at intermediate depth the shaking will have been weakened but will be still very strong.

54km (34mi) SE of Kokopo, Papua New Guinea
282km (175mi) ENE of Kimbe, Papua New Guinea
309km (192mi) SE of Kavieng, Papua New Guinea
367km (228mi) WNW of Arawa, Papua New Guinea
789km (490mi) NE of Port Moresby, Papua New Guinea