A Dublin City Council (DCC) commissioned report has placed a question mark over whether the Croppies Acre is an unmarked burial ground.
The famous park on the north side of the Liffey is considered to be the burial site of so-called "croppies" who took part in the United Irishmen Rebellion.
Archaeology Plan were engaged to examine a section in the north of the park to determine if proposals to widen Benburb Street to accommodate a Liffey cycle route would interfere with any archaeological artefacts in Croppies Acre.
The burial site is thought to be located south of the area which was examined. The 1798 Memorial Park marks the spot where the mass grave is thought to be.
The report notes that "no evidence for human remains or the burial ground at Croppies Acre was noted" during the most recent round of testing last October.
Previous testing done at the potential burial site in 1998 "did not identify any burials, suggesting the location could be inexact", the report continues.
"No additional information regarding this could be ascertained in 2015 and it remains possible that the burial location could be anywhere within Croppies Acre park, or not in the park at all," it states.
However, despite the lack of human remains found during survey which excavated up to 1.9m in places, the report also refused to rule out that the tested area could also be the site of the burial ground.
The survey was carried out as part of the pre-planning process for the controversial Liffey cycle route, which has just seen another major setback.
Four proposed routes for the cycleway along the quays were put out to public consultation last year. The preferred option which emerged from this involved moving the park to the quay wall and running the cycle track through it. Now, however, the council has admitted that all options on the table have "constraints" which cannot be overcome and a fifth option is currently being assessed.
The new option will mean that the first portion of the track will not run Liffey side. The new track would run from the Phoenix Park, north of the Croppies Acre, along Benburb Street to Hammond Lane.
The wall of Croppies Acre will still have to be moved to accommodate the new route, but the affected area has decreased to around 3.5m according to a senior city council engineer.
The loss of the route - which has been four years in the pipeline - was lamented by councillors and members of the public who sit on the Transport SPC of DCC.
Planners will now draw up a detailed plan for the new route which will have to go to public consultation again.