Foreign Secretary Margaret Beckett criticised the tone of debate over the Iraq war as she addressed delegates at the TUC conference in Brighton.
Mrs Beckett has faced criticisms over her Lebanon stance
Mrs Beckett did not face a repeat of the heckling experienced by Tony Blair.
But she said the tenor of debate was now at a point where some people no longer thought there was anything wrong with Saddam Hussein's regime.
She urged a "step change" in relations between the Foreign Office and the TUC to tackle problems around the world.
The prime minister faced booing, cries of "troops out and a walkout from a small section of rail union delegates on Tuesday.
In contrast, Mrs Beckett received only one heckle at the end of her speech, raising concerns about UK policy in Iraq, Afghanistan and Lebanon.
The delegate accused her of being "Blairite to the core".
'Bound to be deaths'
In a questions session, transport union delegate Jimmy Kelly pointed to the "slaughter of so many thousands of innocent Iraqis people" and the growth of the anti-war movement.
To applause, he asked Mrs Beckett if the government regretted anything about going to war.
Mrs Beckett replied: "Of course any military action is bound to lead to deaths on both sides and it is bound to be the case that there are regrets for those deaths."
And there had been "episodes of misbehaviour that should never have been done".
But she did not regret either the fact there was now an elected Iraqi Parliament or the growth in parts of Iraq of a peaceful, more secure and more stable regime.
Mrs Beckett said the UK was raising concerns with the Iraqi Government about the freedom of trade unions.
The foreign secretary also faced questions about human rights in China and UK support for European social initiatives.
Mary Bousted, leader of the Association of Teachers and Lecturers, raised fears about UK military aid to Colombia.
If the government thought it was boosting human rights in the South American country, it was not working, she argued.
Ms Bousted told how she had heard on a recent visit to Colombia from political prisoners and others about assassinations, torture and disappearances.
This was part of "state sponsored terrorism", she claimed.
"The British Government's support is being used by the Colombian Government to legitimise its oppression by terror of civil society," argued Ms Bousted.
Mrs Beckett accepted there was a real problem in Colombia and the UK had voiced its concern about the ill-treatment of a range of groups.
She said there was a dispute about whether the abuses were state policy but the Colombian Government was not succeeding in tackling the problems.
"We don't believe the very small amount of military aid we give is a contributory factor," said Mrs Beckett.
In her platform speech, she said the underlying causes of global crises had to be confronted to prevent future conflict and flows of refugees.
She defended moves to encourage human rights in failed states, saying: "We must never fall into the trap of thinking that pushing democratic values in the world is some sort of unacceptable cultural imperialism."
Mrs Beckett said the Foreign Office should be doing a lot more with the trade union movement, which could influence international organisations.
"Come to us with your ideas and your suggestions," she said.