MPs have expressed their fears about the humanitarian costs of a war in Iraq.

International development secretary Clare Short faced repeated questioning by MPs on Wednesday about what plans were in place to protect Iraqi civilllians in the event of a war.

Short told the Commons that her department was "fully engaged" in telling the world about the humanitarian consequences of a war and conceded there was a major problem in the Middle East.

The minister, a leading "dove" in the Cabinet, said the UN had not yet been allowed to take the lead in the humanitarian effort, which could have disastrous consequences.

"If there is to be military action the authority of the UN must be upheld," she told MPs.

"People are in very bad shape, 60 per cent are dependent on the oil for food programme which is likely to break down."

Labour backbencher Ann Clwyd, who has consistently campaigned on behalf of Kurdish refugees, asked if any plans had been made to protect Iraqi civilians against chemical attack.

"The risk of chemical and biological weapons is one of the most serious risks that we face. It is not possible for anyone to give a guarantee of protection," said Short.

Conservative spokesman on international development, Caroline Spelman, quizzed the minister over the admission that co-operation with military planners had not been good.

"I take the old-fashioned view that it is right to tell the House of Commons the truth. There has been an improvement," said Short.