A total of 26 families are set to be spoken to by police following a tissue sample storage probe at South Tyneside District Hospital.
An audit, completed two years ago, found some samples - taken as evidence during investigations into deaths - dating back 20 years ago.
It is understood the samples were taken to the hospital by a pathologist who covered a large area of the North East.
Police forces nationwide began carrying out audits in 2010 after it became apparent human tissue samples going back many years may have been retained. All the cases in South Tyneside pre-date 2006, when the Human Tissue Act 2004 came into force.
When the story broke, last week, Northumbria Police had refused to disclose how many families they were speaking to in the area, while Cleveland Police revealed they were speaking to 13.
However, the force has now revealed they are speaking to 26 families in the area.
Temporary Assistant Chief Constable Vanessa Jardine said: “We understand the gravity of this situation and the devastating affect it has had on the families involved.
“The human tissue samples of cases that happened many years ago have been identified and we have specially trained officers contacting relatives of 26 people to inform them of this. We are doing this with the utmost sensitivity and it is our priority to make sure this is done as quickly and sympathetically as possible.
“We have taken this matter incredibly seriously and since this came to light have worked tirelessly to identify and speak to the families of those affected and are doing all we can to answer the questions and concerns they have.
“We fully recognise the importance of carefully managing the retention and storage of human tissue samples collected for investigative purposes to ensure they are obtained, and retained and disposed of, in line with the Human Tissue Act.
“In 2006 a new law was introduced as result of such errors and we fully support this legislation and have instructions in place to prevent this from happening again.”