Brandon Lewis made the comment amid a gathering row over the money the prince accepted from the former prime minister of the Middle Eastern state.
However, the Northern Ireland secretary avoided a question about whether the actions of the Prince of Wales threw his judgement into doubt – arguing that it was not “appropriate” for a government minister to answer.
The Sunday Times revealed that the €1m was one of three lots of cash, totalling €3m, that Prince Charles personally received from Sheikh Hamad bin Jassim bin Jaber Al Thani.
Clarence House said the money was “passed immediately to one of the prince’s charities”, who “carried out the appropriate governance and assured us that all the correct processes were followed”.
Asked if the prince should have accepted the cash, Mr Lewis said he was “confident” from his dealings with the palace that the matter will have been dealt with properly.
“As long as it’s following the law and it goes through proper due process, I think that’s fine,” he told the BBC’s Sunday Morning programme.
“We shouldn’t even really be talking about it,” he said, ahead of crucial elections to the executive of the 1922 Committee of Conservative backbenchers next month.
“We have had a vote, had a decision made,” Mr Lewis told Times Radio, adding: “We all get on, we come together, we focus on delivering for people across all these policy areas where we are all in agreement.”
The Northern Ireland secretary also argued that it was “absurd” for the EU to threaten a trade war with the UK over London’s plans to collapse the Northern Ireland protocol – because sanctions on Russia have not been implemented fully.
Both the Irish prime minister, Micheal Martin, and the European Commission vice-president, Maros Sefcovic, have stepped up the war of words in recent days.
But Mr Lewis said: “It’s absurd for … Europe to be talking about that kind of language of a trade war, particularly when we’ve not yet seen Europe fully putting sanctions on Putin for an invasion of Ukraine.”
He claimed: “What we’re talking about is fixing some of the issues in terms of the implementation of the protocol that is so detrimentally affecting Northern Ireland.”
Mr Lewis also alleged that “the Jewish community can’t technically practise their religion” – reigniting a previous row over the threat to imports of kosher food.
And he said: “We have seen Stormont collapse. That means the Belfast/Good Friday Agreement, in all three strands, is either under pressure or not functioning at the moment.”
The Bill to override the protocol, which Mr Johnson hailed as “fantastic” when he signed it in early 2020, returns to the Commons on Monday.