The Jewish Labour Movement has said it is "encouraged" by Sir Keir Starmer's commitment to change the party's rules and culture to eradicate anti-Semitism.
But following talks with Labour's leader, the group said it wanted to see "actions, not just words".
Issues discussed included Labour's response to an imminent report into its procedures by the equalities watchdog.
Sir Keir has promised an independent complaints process to help to rebuild trust among the Jewish community.
Following Monday's meeting, Sir Keir said it would take "strong leadership from the very top of our party to change the culture".
"I want to acknowledge just how difficult the last few years have been for the Jewish Labour Movement and Jewish members of the Labour Party," he said.
He said he and his deputy Angela Rayner, who also attended Monday's meeting, were "intent on working together to make significant progress on tackling anti-Semitism and it is our priority to do so".
Shortly after he was elected last month, Sir Keir pledged to "tear out this poison by its roots" and said his success would be judged on whether former Jewish members who have quit the party in recent years returned to Labour.
Monday's meeting was the first between a Labour leader and the Jewish Labour Movement since 2014, following the breakdown in its relations with Jeremy Corbyn.
The Jewish Labour Movement, the only Jewish group formally affiliated to Labour, was one of Mr Corbyn's most outspoken critics and referred the party to the Equalities and Human Rights Commission.
The watchdog's report into Labour's internal disciplinary processes and the culture of the party under Mr Corbyn's leadership is due to be published in the next couple of weeks.
The watchdog is expected to focus on whether Labour breached the law in how it handled specific allegations, whether it discriminated against Jewish people and whether those who complained were subsequently victimised.
At Monday's meeting, which was held virtually, Labour's leader is understood to have restated his commitment to introducing an independent complaints process, overhauling the current structure in which cases are handled by bodies consisting of politicians and elected members.
'Fit for purpose'
The JLM said Sir Keir had pledged, "as a minimum" to implement all the watchdog's recommendations.
"We have already been encouraged by Keir Starmer's strong condemnation of anti-Semitism, his apology to the Jewish community and his commitment to getting a grip on this problem," its vice chair Mike Katz said.
"But we've always said that actions are what matter. Reforming the party's culture as well as making its management and processes fit for purpose will take time and focus."
The leaking of an internal Labour report into anti-Semitism shortly after Sir Keir's election led to a huge internal row, with allies of Mr Corbyn accusing officials of undermining him as he sought to get to grips with the issue.
Jennie Formby, a key ally of Mr Corbyn, recently announced she was stepping down as Labour's most senior official - a decision which Sir Keir said had been taken by "mutual consent".
Her replacement as general secretary is set to be chosen in the coming weeks.
Those in the running are believed to include Anneliese Midgley, a senior official at the Unite trade union and David Evans, an assistant general secretary under Tony Blair who is currently director of the Campaign Company.