The environment minister said he was astounded and disappointed by the party's refusal to vote in favour of reforms to outlaw stag hunting with dogs.

"It is a sad day for politics in Ireland when the Labour Party decides to vote in support of the continuation of a blood sport," Mr Gormley said. "It appears that for the Labour party, no principle is too cherished to be abandoned if they think there are votes in it for them."

The reforms, instigated by Mr Gormley, will ban stag hunting with two or more hounds - targeting the Ward Union in Meath and north Co Dublin, which has been in place since the 1850s and keeps a herd of about 150 red deer in a field purely for the purpose of the hunt. No other hunt will be affected by the ban and people will be allowed to drive deer off land with dogs if the animals are damaging crops or a plantation.

The minister singled out leader Eamon Gilmore, former leaders Pat Rabbitte and Ruairi Quinn and spokesmen Tommy Broughan and Joe Costello for making u-turns on long-standing party politics.

"For Labour, the vote on stag hunting is about more than animal welfare. It is a test of the party's convictions and principles," Mr Gormley said. "It is a test of whether Labour politicians' words or promises mean anything in 2010, on animal welfare or any issue for that matter.

"It is the latest issue where the party has adopted a reactionary or conservative stance for the sake of populism, such as in relation to the protection of nature sites. The party's pick and mix approach to policy is incoherent and lacks any credibility."

The Labour Party said: "The Party believes that the best way in which to proceed is to strictly enforce and, if necessary, strengthen the licensing regime governing the operation of the Ward Union hunt."

The party said enforcing stricter rules on the Ward Union's licence was the best way forward. "We believe that the Bill is deficient and that there are far more urgent issues of animal welfare that Minister Gormley should be dealing with, such as for instance the serious problem of abandoned horses in urban areas," it said.

Opponents of the ban, who formed a lobby group called Rise (Rural Ireland Says Enough), claim the new laws will be the first step towards all country pursuits such as coursing and shooting being outlawed.