Baroness Chalker, the head of the British delegation to the UN women's conference, criticised Hillary Clinton's forthright attack on China the previous day.
Lady Chalker suggested that America's First Lady had used the Peking conference as a domestic political platform.
"If you look at Hillary Clinton's list of comments and if you heard how she put them, that was a full frontal attack," said Lady Chalker, the Minister for Overseas Development.
Speaking in a radio interview on BBC Radio Four's Woman's Hour, she added: "I don't think that helps to change things. We work by quiet diplomacy ...
"When a First Lady, whoever she is, comes to a conference, unless she has been working behind the scenes for a long while, I think delegates feel a little bit it's being used as a domestic platform from abroad, and they don't like that quite so much."
In her speech on Tuesday, Mrs Clinton attacked as "indefensible" China's refusal to give some women visas to attend a women's forum and limits on freedom of expression.
Although the First Lady did not specify any countries by name, her catalogue of human rights violations, including forced abortions and sterilisations, read as a thinly-veiled attack on the host country.
Many delegates to the conference, while supporting the First Lady's criticisms of China's handling of the women's conference and the parallel non-governmental forum, are privately concerned that the speech has again diverted attention from women's issues.
All last week, the forum was clouded by anger at China's intimidating security operation.
Now, the official conference is being overshadowed by the troubled Sino- US relationship.
Mrs Clinton's presence in Peking was only made possible by China's decision to expel the detained American-Chinese civil rights activist, Harry Wu, just days before the forum opened.
After his release, Mr Wu said in California that the First Lady's attendance in Peking would send the wrong message to China over its human rights abuses.