Irish voters reject plan to abolish Senate

Irish voters have rejected a government plan to abolish the country's Senate, a surprise result that deals a blow to Prime Minister Enda Kenny.

Saturday's official results show that the proposed constitutional amendment to eliminate Ireland's upper house of parliament was defeated with a 51.7 per cent "no" vote.

All opinion polls during the monthlong campaign had suggested easy passage of Friday's referendum question.

Kenny's two and a half year old government had asked voters to agree to abolish the Senate, because the 60-senator chamber wields no essential powers and costs 20 million euros ($A29.23 million) annually to run.

Supporters of the Senate's retention argued the government should reform and improve the Senate, not kill it.

Any amendments to Ireland's 1937 constitution require majority voter support in referendums.