Police Scotland is not investigating the SNP’s finances following an MP in charge of the party’s accounts quitting, Scotland’s Deputy First Minister has said.

The force said a fraud allegation relating to £600,000 of SNP funds is “still being assessed to determine if an investigation is required”.

Douglas Chapman, the MP for Dunfermline and West Fife, announced he had resigned as national treasurer of the party on Saturday evening.

He claimed he was not given enough information to do the job.

Questioned on BBC Scotland’s The Sunday Show about whether Police Scotland was investigating “£600,000 of SNP funds that was raised by activists and campaigners and perhaps diverted elsewhere?”, Deputy FM John Swinney replied: “Not to my knowledge, no.”

He added: “I don’t understand quite what’s prompted this. The National Executive Committee has responsibility for scrutinising the party’s finances… and in addition to that the accounts of the party are independently audited by external auditors and are submitted to the Electoral Commission for scrutiny.

“So there’s a huge amount of scrutiny of party finances that goes on.”

Last month, Police Scotland sources told the Scottish Mail on Sunday the force had examined complaints regarding the SNP, but found “no immediate evidence of fraud”.

The party said at the time the allegations were part of a “dirty tricks campaign” and “utterly baseless”.

Mr Chapman took over in the role last year.

On Twitter, he said: “Despite having a resounding mandate from members to introduce more transparency into the party’s finances, I have not received the support or financial information to carry out the fiduciary duties of National Treasurer.

“Regretfully I have resigned with immediate effect.”

It is not clear what led to Mr Chapman’s decision, but SNP business convener and fellow MP Kirsten Oswald said she “fundamentally disagrees” with Mr Chapman’s assessment.

Also on Twitter, she said: “I am disappointed by Douglas’ decision and, as business convener, fundamentally disagree with his assessment of the support and financial information available to him.

“However, I respect his decision, thank him for his contribution to the NEC (National Executive Committee) and wish him well.

“SNP national treasurers have access to detailed financial information and report to the NEC on a monthly basis.

“The NEC can request any additional information it requires.

“The SNP’s accounts are also independently audited, submitted to the Electoral Commission and published.”

The row prompted criticism from opposition parties.

Scottish Conservative chief whip Stephen Kerr said: “It speaks volumes that even the SNP’s national treasurer can’t get the party to open the books.

“There are obvious questions the leadership have yet to answer for members and even their own politicians.

“But even simple pleas for transparency have further opened up the rift between the nationalists.”

Scottish Labour’s deputy leader Jackie Baillie said: “Douglas Chapman’s extraordinary resignation makes it essential that the SNP are open about the growing number of questions about their finances.

“Earlier this year the party was placed under police investigation for a £600,000 black hole in their finances, launched after three members of their finance and audit committee resigned.

“There are clearly issues that need to be looked at within the secretive inner workings and inner circle that runs the SNP.

“Nicola Sturgeon must agree to open the party’s books to public scrutiny so investigators can get to the bottom of this mess.”