The Phoenix Park has closed its gates more than 30 times so far this year for triathlons and marathons, the Office of Public Works (OPW) has confirmed.
Figures show that in 2009, there were 20 road closures for such events, yet to date in 2010 there have already been 31 closures.
A spokesman for the OPW says the authorities are attempting to keep disruption to a minimum, though this is not always possible.
"We host over two thousand events in the Phoenix Park every year and we always try to organise these occasions in such a way that road closures are kept to an absolute minimum. As you can imagine this is not always possible."
The park has seen a marked increase in demand for charitable activities in 2010, he said, and this is part of the reason for the increased amount of closures, which has frustrated many motorists and regular users of the park.
But Fine Gael spokesperson for tourism Olivia Mitchell said the figures "seem enormous" and is calling on park authorities to arrive at a compromise instead of closing down the park.
"That seems to be an enormous amount in terms of road closures for a public park like the Phoenix Park. There is a balance to be struck between keeping the park open and yet making sure these events can go ahead.
"At the end of the day the park is intended to be for the public and so it is important that it is not seen to be sectioned off for too many of these events in general. There is always the option of compromise where they close off certain sections of the road, and keep the rest open."
Mitchell believes closing down access to the park is "draconian" and says the OPW needs to liaise with park authorities with a view to changing the situation.
Government TDs will take to the park for their own event on the June bank holiday weekend when they will do a run for a designated charity. The park is used as a primary means of access to the city from the west, with over 10 million journeys per year through the area.
In the park's conservation management plan, the OPW states one of its aims is to "facilitate an appropriate mix of recreational use and public appreciation that maximises visitor enjoyment and protects the landscape and infrastructure of the Phoenix Park."