Following a cabinet reshuffle at Nigeria's independence, Wachuku was appointed Minister of Economic Development and Member of the First Nigerian Delegation on the admission of Nigeria to the United Nations. On the eve of his departure from New York, the Prime Minister Sir Abubakar Tafawa Balewa invited Wachuku to his hotel suite and told him that he was leaving him behind as Leader of the Delegation and Ambassador plus Permanent Representative of Nigeria to the United Nations. Wachuku protested to Prime Minister Balewa – saying that he did not join the Delegation with the intention of staying in New York, and that he told his wife, Rhoda, that he would be away for only one week. Balewa replied: "Never mind, I will tell her when I arrive Lagos."