The warning from Michael Moore, the Scottish Secretary, illustrates Whitehall's unease at what UK ministers regard as the First Minister's creeping approach to constitutional engagement.
In a speech to the National Business Convention in Edinburgh, Mr Moore will declare: "It's time to crack on; time is pressing. The sooner we can get the process issues out of the way and get on to the 'Great Debate', the better for everyone and the less damaging the uncertainty will be."
Next week, Mr Salmond will unveil the SNP Government's legislative programme, which will include a Referendum Bill, timetabled for next year. However, the Secretary of State will say if the First Minister and his colleagues wish to stick to their parliamentary plan, they have to agree the so-called Section 30 Order – which will transfer power to hold a referendum from London to Edinburgh – by late October.
Mr Moore will say: "That will allow both of Scotland's parliaments to scrutinise and approve the Order, paving the way to a Bill in the spring. So we need to get on and settle the big questions."
The biggest question at the moment is which way Mr Salmond will jump on a straight yes-no to independence question on the referendum ballot paper or whether there should be a second question, the so-called devo-max option.
The First Minister and his colleagues have adopted what appears to be an equivocal position; they express a personal preference for a single question while talking up the more powers option whenever an opinion poll shows a majority against independence.
Scottish Government sources have told The Herald Mr Salmond will announce the results of the public consultation at the end of September or beginning of October. It is thought he will announce which route he intends to take – one question or two. If he opts for the latter it will spark a war of attrition with the Coalition that will last to 2015 and beyond.
Mr Moore will remind the SNP leadership it was "elected on the promise of a single question independence referendum".
Last night, a spokesman for Bruce Crawford, the Scottish Government's Secretary for Parliamentary Business, said: "It is only right matters such as a more powers option and votes for 16 and 17-year-olds are carefully considered, which is what the Scottish Government is doing."