NHS Greater Glasgow and Clyde (NHS GGC) said one more person – a known contact of earlier cases – has tested positive, bringing the total to 14.
All are experiencing mild symptoms, according to the health board.
It was previously revealed the cluster had a link to an earlier one at the Sitel call centre in Lanarkshire.
The outbreak at the Sitel premises, in Eurocentral business park near Bellshill, was first revealed on July 19 and involved more than 20 cases.
Staff at the call centre help to trace contacts of positive Covid-19 cases for NHS England.
The positive cases in the NHS GGC cluster have been linked to an Amazon warehouse in Gourock and M&D Green pharmacy in Port Glasgow.
Individuals, who may have been infectious at the time, also visited a number of businesses in Greater Glasgow.
These included The Botany bar and restaurant in Glasgow and a boat trip with Sweeney’s Cruises in West Dunbartonshire, both on Sunday.
Individuals also visited The Queen of the Loch by Marston’s Inn in Balloch and Lomond Woods Holiday Park on the weekend of July 24.
Dr Daniel Carter, consultant in public health medicine, said: “All those who have tested positive for Covid-19 and their close contacts have been given appropriate advice and are self-isolating.
“We would like to remind people of the importance of continuing with the general measures to minimise the risk of Covid-19 to themselves and to others.
“These include social distancing, regular handwashing, and being vigilant for symptoms.”
He added: “Anyone with symptoms should immediately self-isolate and seek a test.
“Anyone who needs to do anything over and above these general measures will be contacted by the Test and Protect service and given specific advice.”