Moses Amos said over the Christmas and New Year period, kava exporters drastically reduced their buying price for dried kava chips, in the worst case by almost 90 percent.
Mr Amos said farmers were told the reductions were due to a glut in the market.
However, he suspected they were being exploited by exporters who knew farmers desperately needed cash over the holidays, and when preparing to send their children to school.
"The normal price is being paid between $VT3000 ($US26) to $VT4000 per kilo of dried kava, kava chips.