"I'm not running to be the Pope, I'm running to be the leader of the Labour Party and we have a $50 million gorilla on the other side and his name is John Key."
He said he had years of experience debating on marae and in politics and had no fears about facing Mr Key in Parliament and election debates.
"There is no doubt in my mind I am capable of denting John Key and his Benny Hill routine in Parliament every week."
Up against two former diplomats, Mr Jones is pitching himself as the non-PC, grass-roots candidate. Taking a swipe at those in his party with academic backgrounds - despite himself having an MA from Harvard University - Mr Jones said his style "might not resonate in the common room, but rest assured it will be relevant in the smoko room".
He acknowledged his underdog status, but believed his focus on "bread and butter" issues rather than beltway political issues would have support.
"The Labour brand is a proud and true brand. Unfortunately, we have allowed that brand to become irrelevant in how a whole bunch of New Zealanders see their personal circumstances.
"The 800,000 who didn't vote last time need to see Labour as relevant to what they need to help bring their kids up. It's simple stuff: jobs, income, security, sport, life."
Mr Jones spent the weekend in talks in Northland with his key supporters and iwi leaders before making the final decision.
His decision to enter the race means the preferential system for voting in a new leader will come into effect. If nobody secures 50 per cent of the vote in the first count, the bottom-placed contender will be eliminated and the second choice of that contender's voters will be counted instead.
Late yesterday afternoon, Mr Robertson confirmed he was throwing his hat in the ring "because I think I can unify our party, I represent a new generation of leadership, and because I believe I can lead us to victory in 2014".
Mr Cunliffe has until 10 tonight to confirm his bid.
At the weekend, TVNZ's Q+A programme reported that a telephone poll of 517 people showed Mr Cunliffe had 29 per cent support from voters across the political spectrum, followed by Jacinda Ardern on 15, Mr Jones on 11, Mr Robertson on 10 and Andrew Little on 9.