A rainbow path celebrating Adelaide's lesbian, gay, bisexual and transgender community has been vandalised.

Key points: Adelaide's Rainbow Walk was installed in Light Square in 2016

Adelaide's Rainbow Walk was installed in Light Square in 2016 A man noticed graffiti on it and took spray cans from the vandal

A man noticed graffiti on it and took spray cans from the vandal Police and Adelaide City Council are investigating

White text saying "Jesus Loves You" has been sprayed across the length of the Rainbow Walk, in the city's Light Square.

A passer-by called Tom, who did not want his surname published, said he was driving past Light Square at the time of the incident.

"My boyfriend and I saw as we drove past," he said.

"He [the man] was writing 'Jesus Loves You' on the top of all the printed landmark dates along the walk.

"We pulled around and I got out, snatched his spray can and bag of several more, took some photos of him — he calmly let me and then walked off — and I threw it in our car.

"He didn't say a single thing to me the whole time.

"About 10 seconds later, some police drove past, I waved them down, and pointed him out to them."

SA Police reported a 28-year-old Cowandilla man for marking graffiti.

Adelaide City councillor Robert Simms helped establish the walk and said homophobic vandalism had no place in the local community, especially weeks out from the Feast Festival

"The Pride Walk is about promoting inclusion and celebrating the achievements of the LGBTI community in SA," he said.

"This vandalism is a sad reminder that despite all we've achieved on the road to equality, there is still work to be done to keep fighting homophobia in our city."

The words Jesus Loves You were written several times on the path. ( Supplied )

Adelaide City Council said it would remove the graffiti.

"We're disappointed to see that someone has written across the Rainbow Walk, which was installed in 2016 to celebrate our city's diversity," a council spokesperson said.

"Our graffiti-cleansing team will remove the graffiti tomorrow."