* Second major tremor in as many days
* Initial new tsunami alert lifted
* Government scrambling to send supplies (Recasts; adds comments from Red Cross, World Vision organisations)
SYDNEY, Dec 10 (Reuters) - The Solomon Islands plans to dispatch emergency supplies to areas affected by a 6.9 magnitude aftershock on Saturday, a day after a much larger tremor triggered a tsunami warning that send hundreds of coastal people fleeing into the hills.
General Secretary of the Solomon Islands Red Cross Joanne Zoleveke said the supply boat could take almost 24 hours to reach Makira Island, which lies close to the epicentre of Friday's deeper 7.8 magnitude earthquake. quakes triggered tsunami warnings which were lifted a short time later.
"We are working with the National Disaster Office of the Government and we've mobilised our emergency response teams to accompany the government officers and other international non-governmental organisations that are going on this boat," Zoleveke said.
Makira Island's airstrip services small planes incapable of shuttling the volume of aid required for the relief effort.
"We still don't have that much detail but we know people are really affected by what's happened," Zoleveke said.
Zoloveke said based on reports received by two-way radio, Friday's quake caused significant damage and forced people from homes in the town of Kirakira on Makira Island, about 200 km from the Pacific Island nation's capital of Honiara.
She said she knew of only one reported casualty, a 25-year-old with non-specific injuries. The remoteness of the region and the failure of communications meant it was impossible to know the full extent of any injuries or damage, she said.
Australia has provided A$50,000 ($37,235) worth of supplies and a helicopter to undertake an initial assessment of affected areas to help target relief efforts, Zoloveke said.
Suzy Sainovski of World Vision in Honiara said staff from the humanitarian organisation in Kirakira saw people fleeing to higher ground.
"One of the reasons we need to get them shelter assistance (is) because it's the start of the wet season here," Sainovski said. ($1 = 1.3428 Australian dollars)