The interim review of Liverpool's green and open spaces, commissioned by Mayor Joe Anderson, suggests an extra Â£4.50 contribution is needed per person.
The proposal to increase council tax is one of 31 recommendations made in green activist Simon O'Brien's report.
He warned that Liverpool was "heading to a brick wall" when it comes to maintaining open spaces in the city.
Mr Anderson explained: "Sadly, the 58% cut to our budget by central government has left us grappling with the challenge of finding new ways to fund non-essential services, including maintenance of and investment in our green and open spaces."
Former Brookside actor Mr O'Brien said: "As central government is cutting money left, right and centre, non-statutory provision is the first thing that goes.
"I've suggested other things like tourist levies, which you can only set up nationally unfortunately. I think if we charge everyone who comes to stay in the city Â£1 a head, this problem goes away but we're not allowed to do that yet.
"If I can see a way that maybe you could commercialise a park - perhaps you could put a cafÃ© or a health centre in and bring in revenue - that's good."
He called for residents to give their feedback before a final report is produced.
A city's parks could be funded by an increase in council tax, a report has recommended.