Irish government ministers have been warned not to express any opinion on Scotland's independence referendum.

Official documents also reveal anxiety in Dublin about Prime Minister David Cameron's promised vote on whether the UK should remain in or out of the European Union.

An exit from the EU would be bad for Northern Ireland, which has benefited "immeasurably" economically, financially, socially and politically from the alliance, according to official briefing files.

The papers, seen by the Irish Times, show Cabinet members in Ireland's ruling Fine Gael/Labour coalition as well as Irish diplomats have been cautioned against expressing views on Scottish independence.

Developments ahead of the make-or-break ballot on the future of the United Kingdom are unsurprisingly being watched very carefully on both sides of the Irish border.

The UK is Ireland's largest trading partner and nearest neighbour, with relations having undergone a seismic shift in recent years with several landmark events in the peace process.

Scotland's destiny also strikes into the very heart of the split allegiances in Northern Ireland over maintaining its union with Britain.

Dublin is also concerned about whether an independent Scotland would be admitted into the EU - which the memo points out is still a "hypothetical" question.

"Discussion of it raises complex issues of considerable sensitivity and so the Government must be careful to avoid expressing views prematurely," the documents state.

The Irish Times says the briefing material was prepared earlier this year by the Department of Foreign Affairs.

It suggests a referendum may be required in Ireland to deal with any new arrangements after the Scottish poll in September.

On the debate over the UK remaining in the EU, the papers state: "The Irish position has been that the UK is better off within the EU, and that the union is stronger by having the UK within it."

It adds: "The EU aspect informs much of our work in areas such as agriculture, trade, the environment and indeed right across the areas of North/South co-operation."