MR David Trimble, in a letter to the Tanaiste, Mr Spring, has insisted that the Government should have no say in either the creation or operation of the elected "peace convention" proposed by unionists.
The UUP leader invited Mr Spring to meet him for talks, but only on a limited range of issues.
Mr Trimble wrote: "The peace convention we favour is of course a body which would be elected within Northern Ireland and would primarily operate within Northern Ireland. It would not therefore be appropriate for the Irish Government to be involved in discussions relating to the creation or operation of that body.
"Still less would it be right for the peace convention to be jointly sponsored by the Irish Government.
"We expect that there will be serious talks on substantive issues within or alongside the peace convention. The Irish Government will have to make an input on certain issues, e.g. the normalisation of relations between the Republic of Ireland and the United Kingdom in general and Northern Ireland in particular.
"We will need to discuss the way in which that input is made. It is also desirable to discuss the consequences of the resumption of violence by Sinn Fein/IRA."
In his opening paragraph, Mr Trimble stressed the need to agree an agenda in advance of a meeting between himself and Mr Spring. He also remarked: "In my last letter to you I welcomed your statement that the Irish Government is not seeking to participate in talks dealing with relations within Northern Ireland."
Concluding his letter, he invited Mr Spring to meet to discuss the matters he had raised, "if the above agenda is acceptable to you". He suggested that time be set aside for the meeting on the same day that the two governments have their planned summit meeting.
In a radio interview on Saturday, Mr Trimble took a hard line on the question of Sinn Fein participation in "serious talks" which might follow an election.
On BBC Radio Ulster's Inside Politics programme, he said the position of Sinn Fein within the proposed peace convention was now "problematic". There could be no question of getting involved in substantive talks with Sinn Fein while violence continued, he said.
"They may be able, by virtue of an election, to take their place in the convention and then be in a position analogous to that [which] they are in at present in district councils.
"But, from the point of view of progress into serious talks that we expect to see developing out through the convention, that would have to depend on a genuine acceptance of the Mitchell principles."
He said Sinn Fein would not get "the passport into full negotiations" without a ceasefire, and without an acceptance and an application and an honouring of the Mitchell principles. This meant that disarmament and decommissioning would have to be carried out to show that the principles were being honoured.
Mr Trimble again asserted that unionists had accepted the Mitchell report as a whole - "not just cherrypicked it, picked out the odd paragraph, the way some nationalist commentators have done".
Now, he said, with the necessary "confidence building measure" of elections in place, they would proceed to seek a commitment to the Mitchell principles and to provide for decommissioning "alongside the operation of an elected body in which there would be substantial talks".
Mr Trimble also said that President Clinton had remarked to him that the IRA's resumption of violence had been "damned stupid".
On the same programme, the
SDLP leader, Mr John Hume, said: "We know what Mr Trimble is against, but not what he is for." How did he and his party propose to cope with the problem of ending violence, Mr Hume asked.
The great tragedy was that the Mitchell report had not been implemented, Mr Hume said. He believed there would still be peace today "had the [British] government invited all parties to the table and asked them to commit themselves to the principles of the Mitchell report".
Mr Hume repeats his call for a referendum, saying there was a very powerful mood for peace among ordinary people, and they should be let speak.
He said elections were a very different matter to a referendum. In an election, "you're electing 90 individuals, you're going to have hard line mandates all over the place, making negotiations even more difficult."
He rejected a call by Mr Trimble for the SDLP to cut off links with Sinn Fein. Mr Hume said he would "keep all doors open to everyone".