The Iraqi army and police should be able to take charge of their own country within a year, Foreign Office Minister Kim Howells has said.
Amara has seen more violence in recent days
He said he would be "very surprised" if there were not enough Iraqis trained up to take on coalition forces' work.
It comes despite UK troops being put on standby to help Amara, where power has been handed to Iraqi forces.
Defence Secretary Des Browne echoed Mr Howells' comments but said there was no commitment to a specific date.
Mr Howells told BBC Radio Five Live: "I would have thought that certainly within a year or so there'll be adequate trained Iraqi soldiers and security forces, policemen and women and so on, in order to do the job.
"I mean I'd be very surprised if in a year's time there isn't that kind of capacity there for taking on a lot of the work that's done at the moment by the coalition forces."
Mr Howells added: "The problem is we do not know what the state of play is vis-a-vis the militias - how well armed they are and how sustainable their present rate of fighting is."
He said they had to keep talking to the generals and intelligence services "who watch these things very carefully".
Mr Browne said he thought Iraqis would be capable of looking after their own security within about the next year but that he would not be tied down to a specific date.
Asked directly when he thought British forces would be out of Iraq he said: "When the job is done."
Prime Minister Tony Blair said this week that withdrawing troops prematurely would be "disastrous".
Shadow foreign secretary William Hague called for a full debate in the House of Commons on the situation in Iraq, in the light of the US Baker Commission's review of American options - due to be published after the 7 November congressional elections.
He told BBC One's AM programme MPs needed to know "that there is British influence in the decision, not just solely an American decision".
Mr Hague added: "The question is how to be able to withdraw coalition forces on some reasonable timeframe, sooner rather than later, while leaving behind a democratic Iraqi government and security stability in most parts of the country."
General George Casey, commander of the multinational force in Iraq, said in August that Iraqi security forces would be able to take on security responsibilities for the country in the next 12 to 18 months.
US President George Bush, who says military tactics need to keep changing in order to beat the insurgents, held talks with General Casey and other commanders on Saturday amid continued bloodshed in Iraq.
And British Army commanders said the southern city of Amara was "calm but tense" after hundreds of extra Iraqi troops were sent there.
Clashes between police and up to 300 gunmen left at least 30 people dead and 100 injured on Thursday and Friday.
UK troops had pulled out of Amara because it was considered "relatively quiet".
Basra and Maysan are the only two provinces still under British control, following transfers of power in Dhi Qar and Muthanna provinces earlier this year.