The other AIB Junior Cup semi-final between Monivea and City of Derry had been moved from the Castle Grounds to the Sportsground, following a pitch inspection.
The cup tie was set to kick off at 6.30pm, but following a second pitch inspection at the home of Connacht Rugby, both the Connacht v Leinster and Monivea v City of Derry games have been called off.
Meanwhile, the Leinster Branch issued the following statement: "The Leinster Branch has cancelled all club rugby games in the province over the weekend due to the adverse weather conditions.
"While there are many frozen playing pitches which are unplayable, the decision is primarily based on safety concerns as Garda advice is that many of the roads throughout Dublin and the country, both primary and otherwise, are potentially dangerous to travel upon."
In Munster, the two ODM Munster Senior Cup semi-finals down for decision this afternoon - Cork Constitution v Young Munster at Temple Hill and Shannon v UCC at Tom Clifford Park - have been postponed.
The AIB League Division 2 clash of Munster rivals Clonakilty and Thomond was initially given the green light to take place at Shannonvale Cross, but news of a postponement came later in the day.