SNP hopes of winning Glasgow in next year's council elections have suffered a further setback with the resignation of another party official amid bitter infighting over strategy.

Ari Mack quit as convener of the SNP’s Glasgow Regional Association (GRA).

His departure follows that of GRA Secretary Shona McAlpine and GRA vice-convenor Norman MacLeod in recent weeks, after a series of internal rows about how many candidates to field next May.

The Tories claim the SNP in Glasgow is in meltdown.

The GRA agreed last year to put up 40 candidates – the minimum needed to get an overall majority on Glasgow City Council – but McAlpine and other allies of SNP deputy leader Nicola Sturgeon have tried to reopen the issue, arguing for up to 50.

Supporters of 40 candidates, who included Mack and MacLeod, argued that more candidates risked a split in the SNP vote, and could help Labour return more councillors by default.

However those backing 50 said it would be safer to put up more candidates in order to win a majority of the 79 places on the council.

The issue led to an ugly shouting match at the GRA’s quarterly meeting in June, after which McAlpine and MacLeod resigned.

Mack stayed on, but ran into problems during vetting for council candidates last month.

Last Monday, a special meeting of the GRA decided to revisit the issue and examine whether to put up more candidates in three of the city’s 21 wards, meaning up to 43 candidates in total.

Mack resigned two days later.

The loss of so many key personnel in such a short period is expected to be discussed at the GRA’s next meeting this Thursday.

Since its majority win at Holyrood, the SNP has made defeating Labour in council elections in 2012 a top priority, with Glasgow the main prize.

SNP progress across the west of Scotland would also be key to winning an independence referendum.

The GRA splits, first revealed in the Sunday Herald last month, have made both aims more difficult, and have also delayed the selection of council candidates in the city.

One SNP source claimed the fighting was being driven by supporters of Sturgeon, many from the Asian community, who had joined the party in the expectation of getting the chance to stand as candidates.

David Meikle, Glasgow’s sole Tory councillor, said: “This latest setback shows the SNP election campaign in Glasgow is in meltdown.”

A Labour source added: “The long-running feud between Nicola Sturgeon’s faction and the rest of the Glasgow SNP is bubbling up yet again. The SNP are clearly more interested in putting party interests before the people of Glasgow.”

Mack did not return calls.

An SNP spokeswoman said: “The SNP is preparing to fight next year’s council elections from a strong base after winning record support across the city in May. We are working hard to move Glasgow forward in 2012 after years of Labour neglect.”