Labour has urged everyone in Scotland that shares the party’s values to become a registered supporter, which will entitle them to a vote in the forthcoming leadership election.
Every vote will count towards the final result for the first time, after Labour voted to scrap the electoral college system which split votes in to elected members, supporters and unions.
New members will also be eligible for selection for forthcoming elections, after Labour overturned a rule which gave sitting MSPs an automatic right to re-selection and a place at the top of the regional lists.
Mr Gray said: “These radical new reforms will set Labour back on the road to regaining the trust of the Scottish people.
“I want as many people as possible to join us on that journey, which is why these new reforms will make it easier for supporters to get involved.
“We need to attract the brightest and best people in Scotland who share our values. This is not the time to narrow the pool of talent representing the Scottish Labour Party.
“Our message to those who want a fairer nation and the chance to get on in life is very simple - help us transform Scotland. Whether you’ve been a supporter for years or voted Labour for the first time at the general election, you can find a home in our party.”