Pohiva Tu'i'onetoa made the proposal as parliament met for the presentation of the government's budget.
Finance minister Tevita Lavemaau presented the US$253 million budget, with a forecast US$25 million deficit for the year ahead.
Mr Lavemaau said he thinks this is Tonga's biggest budget deficit ever.
He added that a US$181 million loan from China is due to be paid in 2024, suggesting that Tonga plead with Beijing to cancel the repayment.
Parliament will debate the proposed salary reduction.