A former SNP Cabinet Secretary has criticised proposals which would make it easier for the party to suspend members in the wake of the Alex Salmond sexual harassment row.

MSP Alex Neil, speaking ahead of the SNP conference starting in Glasgow, said his party had to be “very careful” about pushing through internal constitutional changes which may not protect the rights of members.

He added: “Personally I wouldn’t vote for it until I saw what the criteria was going to be.”

Mr Salmond is being investigated by police after a Scottish Government probe into claims he sexually harassed two women.

The initial probe was handled by the Government, not the SNP, and Nicola Sturgeon said her party had “no legal basis” to suspend her predecessor.

The SNP National Secretary, under the existing constitution, can only suspend members after concluding they have broken party rules.

Mr Salmond voluntarily quit the party he has been a member of for decades as criticism of Ms Sturgeon intensified for what her critics described as inaction.

It then emerged that the SNP is proposing changes to its constitution which would increase the scope to suspended members.

The new constitution would state: “The National Secretary may suspend a member from exercising any or all rights of membership while investigations are being investigated and considered. In all cases where this action has been taken, the suspension will be regularly reviewed.”

Members could also be compelled to make “appropriate restorative action, such as an apology”, forced to “undertake appropriate training”, or be punished with “any other proportionate sanction or requirement”.

Angus MacLeod, the current national secretary, said in his introduction that the proposals amounted to a “modernising of our disciplinary processes” and an enhanced approach on “bullying, harassment and social media use”.

Mr Neil, who has been an MSP since 1999 and who served in the Salmond and Sturgeon administrations, told the Herald on Sunday.

“We need to be very careful what we are doing here. There may be circumstances when it is perfectly justifiable to suspend somebody right away, but it should be under very, very strict criteria. Personally I wouldn’t vote for it until I saw what the criteria was going to be."

He added: “I don’t think we can give an open book to the National Secretary. We need to build in guarantees.”

Mr Neil also said there is a “lot of nervousness” about the proposal: “This should not be agreed until human rights guarantees are built in around it.”

Asked whether some party members already believe SNP headquarters is heavy-handed, he said: “There’s no doubt about that.”

The SNP’s 84th national conference will start today with a welcome by Glasgow Lord Provost Eva Bolander and an address by Justice Secretary Humza Yousaf MSP.

Debates on migration policy, reusable plastic and domestic abuse will take place, followed by a debate on the internal constitutional changes.

Speaking ahead of the gathering, Ms Sturgeon said the SNP would set out plans to help people with the cost of living, improve the NHS and boost jobs and wages.

“Thousands of delegates will gather in Glasgow this week as the SNP sets out how we are giving hope to people across the country - both through our actions in government and our vision for an independent Scotland.

“At this most crucial time in the UK’s negotiations on its future relations with the EU, Labour and the Tories have fallen apart into bitter faction-fighting.

“The people of Scotland deserve better than the despair, incompetence and chaos of Westminster – and the SNP is offering a clear message of hope.

She added: “In government, we’re building a fairer and more prosperous Scotland – protecting the most vulnerable in society, making the tax system fairer and investing in our NHS and other vital public services.

“And we are laying the foundations for a brighter future for Scotland – with a radical extension of free childcare, school reforms to raise attainment, world leading action to tackle climate change, building a new national investment bank and delivering record numbers of affordable homes.”

Scottish Labour leader Richard Leonard criticised Ms Sturgeon’s record in office:

“As delegates gather for SNP conference in Glasgow this weekend, the big choice in Scottish politics could not be clearer – the austerity economics of nationalism with the SNP and the Tories, or investment with Labour.

“The conference begins just days after official statistics revealed the brutal impact of austerity in Scotland where life expectancy has fallen for the first time since Thatcher was in power a generation ago."