Ireland has scored an emphatic, record-breaking 21-6 victory over Australia at a wet and windy Lansdowne Road in Dublin, their biggest winning margin in a home Test against the Wallabies.

Apart from the opening 10 minutes when Australia took a 3-0 lead with a penalty from captain Stirling Mortlock, the home side dominated the first half, using their possession to repeatedly test the visitors' disciplined defence.

Fly-half Ronan O'Gara made things even 17 minutes in with a penalty before wing Denis Hickie scored the first try of the match 10 minutes later.

Fullback Geordan Murphy followed that with another try in the closing minutes of the half, having earlier had one denied when he touched down just short of the line at the end of 21 phases of play in which the Irish laid siege to the Australian defence.

A conversion from O'Gara gave Ireland a well-deserved 15-3 lead going into the break.

Again it was left to Australia to open the scoring after the interval with a penalty from centre Mortlock, but Ireland quickly restored their half-time lead with another penalty from O'Gara.

The fly-half then took his personal tally to 11 points when he extended that lead to 21-6 with another penalty mid-way through a tryless second half where driving rain seemed to sap the energy of both sides.

Tempers frayed at one stage with South African referee Marius Jonker handing out yellow cards to Ireland's Denis Leamy and Australia's Mat Rogers and Phil Waugh but the visitors failed to take advantage of a more scrappy second half.

Despite a lacklustre final 20 minutes from the Irish, the home side still retained much of the possession and Australia never seemed to pose a serious threat.

The victory surpassed Ireland's previous highest margin of victory at home to Australia of 18-9 in 2002.

The 15-point margin also equalled Ireland's biggest margin of victory home or away against Australia, matching the 27-12 win Ireland chalked up in Brisbane in 1979.

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