An Australian journalist and a photographer on aid boats heading for the Gaza Strip have not been heard from Monday, and 10 people were reportedly killed during a clash with Israeli commandos.

Fairfax journalist Paul McGeough and photographer Kate Geraghty were last heard from around 12 p.m. on Monday while on board the MV Samoud, a Fairfax spokesman told Australian Associated Press.

"They're on assignment covering the flotilla," the spokesman said.

"They've been moving from boat to boat ... and we last had contact with Paul around lunchtime today. He said they (Israeli forces) were beginning to jam communications and we haven't been able to communicate with them since."

An Israeli television network reported on Monday that at least 10 people were killed and another 30 injured on board the Turkish passenger ship, the Mavi Marmara, which is part of the flotilla of aid boats.

The flotilla was headed for Gaza to deliver aid but an Israeli blockade has been in place since 2007.