The searching for objects possibly related to the missing Malaysian Airlines flight on Friday has changed from radar detection to visual sightings, Australian Maritime Safety Authority (AMSA) said.

"Noting that we've got no radar detections yesterday, we have re-planned the search to be visual, so aircraft flying relatively low with very highly skilled and trained observers looking out of the aircraft windows and looking to see objects," AMSA Emergency Response Division General Manager John Young said in a pre- recorded video on Friday.

AMSA held no press conference on Friday.

Young said Thursday's search was aimed to relocate objects that are possibly related to two objects spotted by satellite imagery. However the weather conditions "were not particularly good."

"Today, the forecast is better. The forecast was for some low cloud but relevantly clear underneath the cloud," he said.

He said the switch to visual sightings means "we will need more aircraft for that for a search area that type."

AMSA tasked five aircraft for Friday's search. There are three Royal Australian Air Force P3 Orion aircraft, a Bombardier Global Express long-range corporate jet as a visual search aircraft with State Emergency Service observers aboard, and a U.S. Navy P8 Poseidon.