Assembly members have clashed as it was confirmed Peter Robinson and Martin McGuinness are to make a second investment trip to China in the new year.
Ulster Unionist leader Mike Nesbitt was accused of "small minded-ness" after asking why taxpayers would be funding another trip so soon after the first.
The criticism came from deputy First Minister Martin McGuinness who argued a repeat visit to China is "very important".
Mr Nesbitt, chair of the Assembly committee which monitors the First Minister and deputy First Minister's Office, said Mr McGuinness had spoken of talking with and meeting diplomats and business people, but not Chinese politicians.
"Given that the Chinese party congress coincided with your trip, do you accept that you did not get within 1,200 kilometres of anybody of any real political significance? Is that why the taxpayers have to fund a return trip so early in the new year?" he queried.
Mr McGuinness replied: "The reality is that the trade mission to China was organised well before the Chinese communist party convention was held. At that stage, the First Minister and I agreed that we would lead the delegation and be part of it.
"It was not our fault that the Chinese communist party decided to change the date for its event. The advice that we received from diplomats on the British and Irish side was that the First Minister and I should still go.
"I think that it was a very important first entry to China and that the opportunities that presents to us are unlimited.
"That was a very small-minded question from the leader of a party that is now, clearly, much smaller than it was previously (and is in the view of some) in tatters."
And the Sinn Fein minister later added: "When we decided to undertake the mission to China, we spoke with a number of people who are acutely aware of what is required to build relationships in China. The advice that we received was that you do not go once to China; you have to build relationships with the Chinese political leaders and the business community in China.
"There is an art to that.
"That art is well-made in a book published by, I think, Trinity College Dublin, which clearly indicates the way in which business people from this part of the world should approach the way that they build contacts with the Chinese business community."
The deputy First Minister said that the economic mission by more than 30 organisations had helped to raise the profile of our businesses to potential buyers and business influences in China.