Labour TD Aodhan O Riordain has hit out at his Labour leadership rival Alan Kelly saying that a "sharpen the elbows and back to basics" approach will not get the party anywhere.
Mr O Riordain took several veiled swipes at Mr Kelly's style and approach to politics in an interview with the Sunday Independent.
His comments are likely to raise the stakes of the race to succeed Brendan Howlin which will conclude in early April. The two men announced their leadership campaigns last week.
"If we think that shouting at other political parties will get us traction it won't," Mr O Riordain, who won back a Dail seat in Dublin Bay North earlier this month, said.
"By thinking we can just sharpen the elbows and get back to basics it's not going to get us anywhere. We have to completely change the way we do politics.
"We have to stop being Leinster House obsessed and stop being obsessed with programmes that people who are in politics are obsessed with."
Mr Kelly launched his leadership campaign last week with a declaration that Labour needs to "get back to basics". He has previously spoken of his long history with the party and remarked on how Labour is "the party I was born into and which has always been in my very DNA".
But Mr O Riordain said he was not born into the party and had no prior ambition to lead it.
"I don't have Labour in my DNA, I don't even know what that means. What we need to be criticising is not other political parties because that's just a bunch of politicians having a go at each other," he said.
"We need to be criticising the rise of the far right, tax exiles, we need to be criticising racism, homophobia and poverty-paying employers. That's what we need to campaign and talk about."
He added: "I know there is an attractiveness within political parties for a politician who gives it socks, is forceful in their option, and is a fearsome debater, and that's all fine.
"I like to think I have my own sort of abilities in that direction as well. But politics is about people's lives, it's not about trying to outdo other parties by criticising them taking them down."
Mr Kelly said last night that Labour "absolutely has to get the basics right" and that he intends to reinvigorate and reorganise the party from the bottom up if he wins the party leadership race.
The Tipperary TD said: "The rebuild of Labour is not going to happen overnight. It will take time, hard work, energy, innovation and passion.
"At the same time we must give strong and effective opposition. This will, as I've said all week, involve supporting policy that will be in the interest of the people.
"But it will also involve vigorous and relentless pursuit of government on issues that need to be challenged, just as I've done in opposition with the cervical cancer controversy, the Children's Hospital.
"We have to make the party relevant to national discourse if we are to achieve anything and I intend to do that."