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.

President Juan Manuel Santos said the authorities do not know how many people are still missing.
Heavy rains caused the river Liboriana, in the town of Salgar, to burst its banks, triggering the landslide.
Much of the village of Santa Margarita, south-west of the provincial capital, Medellin, was swept away when the disaster hit early on Monday.
Rescue teams and residents have got together to dig through rouble in the hope of finding survivors.
After visiting the scene of the disaster, Mr Santos declared a state of emergency and promised to rebuild the houses.
"We cannot bring the dead back, which we regret deeply, and we will support the families (of the victims)," said Mr Santos earlier.
"But we have to move on from this tragedy, and look ahead with courage and fortitude."
"The priority now is the hospital," said the president.
Earlier on Monday, gas and electricity services in the town were suspended as a precautionary measure.
The Colombian Air Force and police have sent helicopters to the area. More than 160 soldiers are working in the emergency effort.
Some 100 people have been evacuated from high-risk areas.
Local official Zulma Osorio spoke of a "tragedy of enormous proportions".
Mud, rocks and tree trunks destroyed many houses in poor neighbourhoods close to the river.
Resident Jorge Quintero described his ordeal when the landslide hit the village: "When I felt my house shaking we got out, my family and me. When we got out, we were stuck in the middle of the landslide, it was coming from both sides and we were in the middle.
"I said to my wife, let's hold each other and hope that God saves us and I know he gave us his hand because here we are, alive, still frightened, but still alive."
More rain is expected in the are in the next few days.
A city's parks could be funded by an increase in council tax, a report has recommended.
[NEXT_CONCEPT]
More than 50 people have been killed in a landslide in Antioquia province in north-west Colombia, officials say.