Mr Yates said poor communication infrastructure had made it hard to assess the immediate impact in Makira.
"[One community] that has been in touch with us said they are calling from up the hills, which is good, they activated their own emergency plans and know what to do, so we are happy.
"The warning has been issued ... at this stage, communication difficulties are hampering our ability to get clear information."
He told the Solomon Islands Broadcasting Corporation there had been reports of landslides in Temotu and Makira provinces.