The UK government "stands ready" to hear from the kidnappers in Iraq of peace activist Norman Kember, Foreign Secretary Jack Straw has said.
Mr Kember has been held since last Saturday
No official contact has been made but officials say they are ready to listen if the hostage takers make contact.
There had earlier been reports of direct contact being made with the kidnappers but this has not happened.
Mr Kember, 74, from Pinner, north London, was one of four men kidnapped in the Iraqi capital last week.
Mr Straw used a TV appeal to condemn the kidnappings but said the UK government would listen to the hostage-takers.
He said: "The British government's policy on negotiating with kidnappers, and on ransoms is well known and very clear.
"However, as we've said in the past, if the hostage-takers want to make contact with the British government, we stand ready to hear what they have to say."
Process under way
Mr Kember is being held with American Tom Fox, 54, and Canadians James Loney, 41, and Harmeet Singh Sooden, 32.
Last Friday Arab broadcaster al-Jazeera aired a video in which the kidnappers threatened to kill the four men by Thursday unless all prisoners in US and Iraqi detention centres were released.
On Monday the foreign secretary said: "Hostage taking is never a legitimate way in which anyone should expect to achieve their aims."
But he said a process already under way on the release of prisoners had seen 12,000 freed, with another 700 due to be released this week.
"This process is going to continue and is entirely unrelated to the pressure of events."
A Foreign Office spokesman told the BBC no official contacts had been made with Mr Kember's kidnappers. "Sadly while we wish this was the case, it has not happened," he said.
Earlier the Muslim Association of Britain was among a number of Muslim groups and leaders to call for the release of the hostages.
It said it was "saddened" by the kidnappings.
A spokesman said its representative Dr Azzam Tamimi had been at a conference on the Middle East in Yemen.
Members of Hezbollah and Hamas are among those calling for the release.
Meanwhile, an anti-war envoy is continuing to meet Sunni Muslim groups in Iraq in a bid to secure the four men's release.
On Sunday, Mr Kember's wife Pat appealed for his release on al-Jazeera. Mrs Kember said her husband, from Pinner, north London, and his friends were allies of Iraq.
"He went to Iraq to help the Iraqi people to stop the spread of abuse and to understand the situation in order to make Iraq a safer place," she said.
He had travelled to Iraq as a "gesture of solidarity" with Christian Peacemaker Teams (CPT), a Canada-based international peace group.