He said the issues he took particular interest in included New Zealand parents who had children in Australia born with significant impairment or disability. "That's an area long overdue for more work."
He said he had told both Mr Cunliffe and Prime Minister John Key in the past that he was committed to better economic and people-to-people relations.
Mr Shorten was elected leader of the Labor Party in October last year after the party lost the election under former Prime Minister Kevin Rudd.
He is doing better in the polls than Mr Cunliffe - helped by new Prime Minister Tony Abbott, whose Government has just introduced a radical slash and burn Budget.
He said that Budget was one of the reasons Abbott was struggling. "In terms of New Zealand, you can never assume someone will or will not win the election. It's a matter of having the best policies and the best ideas."
Asked what advice he might give to Mr Cunliffe, given the Australia Labor Party's factionalised structure, he said he was not here to give advice to New Zealand Labour.
"What I do know is that when Labour concentrates on being a membership based party and not a faction-based party, when Labour concentrates on being a party for all people, not just sections of the economy, then Labour does best."
He also declined to offer a view on the Internet Mana alliance and whether Labour should work with them.