Tonight and tomorrow the four Irish provinces will contest the quarter-finals of the Celtic League. That the four have qualified, and with some style at that, reflects great credit on all concerned.

With Leinster and Munster having topped their groups and with Ulster and Connacht having finished runners up, what now are the chances of an Irish clean-sweep this weekend and so making the semi-finals next weekend an all-Irish preserve? It would be a worthy achievement, even though the Celtic League cannot be put into the same category as the Heineken Cup.

The two matches on the schedule tonight are certainly attractive pairings. Leinster against Newport and Ulster against Neath. Tomorrow, it is Munster against Llanelli at Thomond Park and Connacht against Glasgow in Galway.

There is tremendous enthusiasm for, and interest in, rugby among the Irish public right now. Even those who in the past had no more than a casual interest are now attending matches as we have seen in the attendances at the matches involving the provincial teams. Friday night rugby at Donnybrook and Ravenhill is drawing great crowds and creating a great atmosphere.

The big increases in interest and enthusiasm have been nurtured on the success of the national team, of the four provinces in the Celtic League and, in the case of three of them, in the Heineken Cup. Allied to those factors is the fact that some really good and exciting rugby is being played. Irish rugby must continue to capitalise on the current climate.

But the rainy days could come too and, while as long as the provinces keep winning, the crowds will come, the public mind can be a vague and fickle force. Is there too much representative rugby? Has the right balance been struck between the needs and the demands of the clubs and the provinces?

The Heineken Cup is a superb competition and grows ever stronger. But, despite the current success, is there a danger that too high a price will be paid for the Celtic League in some respects? Now, while enthusiasm and interest are very high, we will enjoy the good times. But as they saw and learned in the southern hemisphere, most notably in South Africa, enthusiasm can wane and so can attendances when the scene is saturated with representative matches.

So a right balance must be struck and that is something to exercise the minds of the legislators here and across the channel.

This is the first season of the Celtic league and, certainly from an Irish perspective in respect of attendances, performances and results, it has made a profound impression. That, alas, cannot be said across the board of all those participating.

From a few sources across the channel, we hear the sounds of some little element of discontentment. Well, I suppose it would be different if their efforts were being marked by success and good attendances.

For instance, while the Irish can claim four out of four of their participants in the quarter-finals and all four with home draws as a result of their exploits, not so the others. The Scots have one quarter-finalist from two participants - and then we come to the Welsh. The Welsh have the biggest representation of all in the league with nine clubs. They have managed just three quarter-finalists. Llanelli came fourth in Pool A, while Neath and Newport came third and fourth respectively in Pool B. Two great clubs such as Cardiff and Swansea failed to qualify.

In the context of the Heineken Cup, with two pool matches to be played, the Irish provinces are also much better-placed than their Welsh and Scottish counterparts, especially Munster and Leinster who top their pools, both with 100 per cent records.

The Leinster team is already assured of a quarter-final berth. Ulster stand second in their pool with three wins and one loss. Both Scottish representatives are out of contention. Llanelli with three wins from four games stand second in their pool behind Leicester and they are best-placed of the five Welsh representatives.

The Leinster-Newport match will be the third meeting this season between the sides with Leinster having won both Heineken Cup matches against the Welsh team. But that will scarcely induce any complacency in Leinster who had a very close call in the match at Rodney Parade. Leinster will, too, be defending a superb 100 per cent record this season with seven wins out of seven in the Celtic League and four wins from four matches in the Heineken Cup.

Ulster's match against Neath brings them into opposition against the only team to beat Munster this season, which Neath did in the early stages of the Celtic League. So, a note of caution there for Ulster who lost to Leinster and Llanelli in the Celtic League group stage.

Connacht, who lost to Munster and Edinburgh in the league, take on a Glasgow team that drew with Ulster in the group stage, but wins over Neath, Newport, Cardiff and Caerphilly will elevate Connacht's confidence of making home advantage pay. Llanelli, a team with an Irish connection in the Easterby brothers, Simon and Guy, visit Thomond Park, and that venue has been an unbreachable fortress for all invaders.

Munster has never lost at this venue in the Heineken Cup or Celtic League. An entertaining and let us hope another fruitful weekend for Irish rugby is in prospect.