Independent auditors have been brought in to assist Scottish Labour officials probing financial irregularities in the first minister's constituency.

The discovery in the accounts of Jack McConnell's Motherwell and Wishaw constituency led to the move by party officials.

A spokesman said the party's top Scottish official was keen to ensure that the accounts were subjected to rigorous scrutiny.

He said: "They were brought in because early on in the inquiry, general secretary Lesley Quinn realised we needed professional external auditors to properly analyse the books."

Lesley Quinn sought auditors' help

The spokesman would not name the firm involved and would not say how long the investigation was expected to take.

A party official is understood to be under scrutiny over the apparent misuse of funds in Motherwell and Wishaw for which Mr McConnell is MSP and Frank Roy is the Westminster MP.

Further scrutiny in that constituency also revealed breaches of the law on political donations, with the investigation into that aspect now spreading to other constituencies.

It emerged on Monday that members of rival factions in the Motherwell and Wishaw constituency are fighting for a seat in the Scottish Parliament.

Hugh Mulholland and John Pentland are locked in a head to head battle for a place on Labour's top up list in Central Scotland.

Mr Mulholland is thought to have uncovered the "black hole" in Labour's Motherwell and Wishaw accounts.

Councillor Pentland is a close ally of Mr McConnell and an assistant to local Labour MP Frank Roy.

'Dodge, spin and hide'

As of February 2001, all donations of more than £1,000 - or totalling more than £1,000 from one source in the course of a year - must be notified to the Electoral Commission.

Labour constituency officials elsewhere have been told to check their books.

The Scottish National Party has called for a full investigation by the Electoral Commission and a statement from Jack McConnell.

Party leader John Swinney said: "He cannot continue to dodge, spin and hide behind allies. The time for full disclosure has come," he said.

The controversy has also left Labour in "disarray", said Scottish Tory leader David McLetchie.