The government hopes to secure a deal on Thursday that will see European human rights judges intervene less in British affairs.
Justice Secretary Ken Clarke is hosting a conference of representatives of the 47 member nations of the Council of Europe in Brighton.
The deal, called the Brighton Declaration, is expected to be signed at the two-day conference.
The senior officials said they were "quietly confident" that the draft agreement would be signed on Thursday, but admitted: "It really is like herding cats to get 47 into one sack at one time."
It comes in the wake of the ongoing furore over government attempts to deport terror suspect Abu Qatada and after European Court of Human Rights (ECHR) judges ruled last week that the extradition of radical cleric Abu Hamza and four other terror suspects to the US would not violate their human rights.
In January in a speech at the Council of Europe, Prime Minister David Cameron claimed that the Strasbourg-based court's work defending human freedom and dignity was being put "under threat" due to public unease over some of its decisions.
He also envisaged reforms to the court - reforms which senior government officials last night denied had been watered down into the draft Brighton Declaration.
Also yesterday, in contrast to what Mr Cameron has said, a justice minister involved in the reform talks insisted there was no "great constitutional crisis about foreign judges trying to ride roughshod over British law".
Lord McNally said: "I don't believe we've got some great constitutional crisis about foreign judges trying to ride roughshod over British law or British processes."
Speaking at the Arts and Humanities Research Council conference on human rights in central London, he said the court needs to change because there is a danger of it acting as a "convenient safety net" for under-performing states.
The Liberal Democrat peer said national responsibility for human rights runs through draft plans for reform "like the letters through a stick of Brighton rock".
The Brighton Declaration would ensure there was "an onus at national level" for them to consider all human rights implications, he said.
The ECHR "cannot secure the rights and freedoms of 800 million people and, what is more, we should not even ask them to try", he said.
Instead, the council should ensure that human rights obligations "are properly addressed at a national level".
But he denied that foreign judges were simply trying to overrule British courts.
The draft declaration "leaves the important decisions for Strasbourg and gets the balance right", he said.
Lord McNally also said the European court was still receiving more applications than it could handle, with a backlog of more than 150,000 cases.
Just 45,000 cases were presented to the court in its first 40 years, but in 2010 alone it was asked to consider 61,300 applications.
In future it should "focus on cases which particularly require the attention of an international court", he said.
He added that the draft declaration was "pretty much there" and "starts with national implementation" of the European Convention on Human Rights and how it may be implemented more effectively by states.
Senior government officials said last night that what had been achieved was "very much" what the Prime Minister has set out in January.
One official said they were "confident that the impact on the system itself is very much the impact we were seeking to have".
The reforms would lead to "many fewer cases", another said, but Europe's human rights judges would still consider key cases where they felt "there was a serious issue or a new issue for them to consider".
This would include issues like those raised previously over removing innocent people from the national DNA database, the officials said.
It could also include the controversial case of Jordanian terror suspect Qatada, as the court's ruling in January was the first time that the court found an expulsion would be in violation of the right to a fair trial. But the officials would not comment on Qatada's case.
The senior officials also admitted that the court already had the power to rule cases which had already been properly considered by national courts inadmissible.
But they said the deal expected to be signed today would give the court clear and strong guidance that it should make those decisions "strictly and quickly".
It will also "tighten and define admissibility criteria more clearly", they said.
The declaration should "steer the court very strongly to say if a national court has considered the issue properly, there should not be a role for the court in Strasbourg", one senior Government official said.
The deal follows months of negotiations in which there was widespread agreement that the system was not working as well as it could and "general agreement that the court should take fewer cases", the officials said.
Of the court's backlog of more than 150,000 cases, around 90,000 would be found to be inadmissible.
But around 25,000 were admissible and there were real concerns over how long serious cases were taking to be heard.
From the UK, there were around 900 applications to the court last year, part of a backlog of some 3,000 UK cases, but only eight findings against the UK. This compared with some 40,000 pending cases from Russia.
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