The gap between unionists who will only go into a shadow assembly and nationalists who do not want this can be bridged, Peter Hain has said.
NI Secretary Peter Hain remains optimistic
Mr Hain was asked about Bertie Ahern's weekend remarks that a Stormont assembly could possibly operate for some months without an executive.
The NI secretary said Mr Ahern was illustrating current thinking but a detailed plan had to be worked out.
He added MLAs could not continue to be paid "for jobs they refuse to do".
Mr Hain said there would be an announcement within a month.
The secretary of state said that when a detailed plan for an assembly was completed by the British and Irish governments it would present NI politicians with "a very clear, very stark and for some perhaps very hard choice".
Speaking at the weekend, Taoiseach Bertie Ahern said the two governments' aim was to have a fully functioning assembly with an executive as envisaged under the Good Friday Agreement.
However, he said a deadlock over the formation of that executive should not stop the assembly from operating while there was work for it to do.
Mr Ahern said he wanted to give the assembly a chance and it would not be a meaningless interim assembly.
He suggested it could operate over the summer and into the winter.
However, he warned that time was limited and that if there was no agreement on an assembly with an executive, Stormont would not operate into next year.