IRELAND captain Denis McBride admitted his team paid a heavy price for some untypical half-hearted tackling as their Rugby World Cup Sevens hopes suffered a severe setback.

Ireland seemed to have made a dream start with two tries from Richard Wallace inside the first two minutes of their opening game against Argentina. But poor tackling allowed Argentina to grab a 31-22 win, while the Irish lacked their usual fire as they conceded six tries in a 38-5 rout against impressive South Africa.

That leaves Ireland facing another stern test against the South Africans in the next group stage today when hosts Hong Kong will also be among the opposition as quarter-final places are decided.

Ireland's tournament was just 16 seconds old when Wallace took David Humphreys's neat flicked pass to score, also going over a couple of minutes later. But poor defensive work allowed Argentina to level with quick tries from Gonzalo Camardon and Eduardo Simone. Wing Denis Hickie also got on the scoresheet.

But further scores from Lisandro Arbizu, Facundo Soler and Camardon put Argentina in command despite a late try from Humphreys following a break down the right touchline.

Only Eric Miller scored for Ireland in their second game of the initial group, but Ireland had already been swept aside by a menacing looking South African side for whom Bobby Skinstad scored a hat-trick of tries.