Peter Robinson had pledged to be "whistle-blower'

Mr Trimble and Mr Mallon said they needed assurances from the DUP ministers that the confidentiality of executive committee business would be preserved.

They said the two DUP ministers would still receive executive papers deemed relevant to their departments, but would not receive any other material.

Mr Trimble added that the two DUP ministers would not be invited to attend the UK-wide British-Irish Ministerial Council, also set up under the agreement.

"The first and deputy first ministers will assume responsibility for representing the executive committee on transport matters at the British/ Irish Council, in place of the minister for regional development.

"Neither the minister for social development, nor the minister for regional development will be nominated to attend meetings of the joint ministerial committee which include representatives from the United Kingdom Government and the devolved administrations, discussing UK-wide policy areas.

"Thirdly, pending the receipt of satisfactory assurances from DUP ministers, about the confidentiality and integrity of committee business, the minister for social development and the minister for regional development, will not receive now executive committee papers as a matter of course," Mr Trimble said.

'Immature behaviour'

Mr Robinson said the first and deputy first ministers' action was "high-handed and panic stricken".

"Their behaviour exudes all the qualities one would expect from immature schoolchildren.

"I am, therefore, instructing my department that no official should provide them with any information without my authority.

"I am responsible for my department, not Mr Trimble and Mr Mallon. The first and deputy first ministers do not speak on behalf of the Department of Regional Development," he said.

When Mr Robinson announced his party's strategy to disrupt the workings of the executive in May, he said the DUP ministers would act as the "whistle blowers exposing each of Trimble's further concessions to Sinn Fein/IRA".

But he insisted he had never breached governmental confidentiality and dismissed attempts by the First Minister and the Deputy First Minister to take over his responsibilities at meetings of the British-Irish Council.

DUP exclusion motion

Mr Robinson also announced that his party has tabled a motion to have Sinn Fein expelled from the executive.

It would need to win 60% backing for the proposal in the assembly.

The party plans to rotate DUP members through their ministerial posts if their motion against Sinn Fein is not successful.

It also plans to continue to boycott assembly executive and North/South ministerial council meetings, as it did during the executive's last period in office.

The DUP has also said its ministerial and committee post salaries will be put into a party fighting fund geared towards damaging the Ulster Unionists at the next Westminster election and discrediting the Good Friday Agreement.