Questions have been raised as to why almost $19,000 was spent on a mural in Sydney's CBD that has been torn up after a few months.

The likely Labor candidate for lord mayor of Sydney, Linda Scott, has criticised Sydney City Council over the move.

US artist MOMO was commissioned by the council to paint a multi-coloured mural for the Kent Street underpass.

It was opened to the public in late January - but this week has been bulldozed, 13 weeks later.

Cr Scott said "installing a painted artwork at the cost of $19,000, then ripping it up is not the best use of public money when we have so many other shortages around the city".

City of Sydney commissioned US artist MOMO to paint the mural for the Kent Street underpass. ( Supplied )

City of Sydney said the artwork was always intended to be temporary, as part of a program to display art in unusual public places.

It said the opportunity for the mural arose before scheduled construction took place on the site and there were no additional costs for its removal.

The underpass is now being upgraded to "include improved lighting, a wider staircase, more garden areas and better separation between the cycleway and footpath".

Cr Scott said the money would have been better spent on child care or open space.

"I've asked staff for more information but the bulldozers have already gone in so there's not too much I can do except for express that I don't think this is the right use of public money and that we need change at the City of Sydney at an election," she said.

"We've got huge shortages of child care, we've got a stark lack of sporting fields in the city of Sydney.

"I think public monies could have been used to fill these infrastructure backlogs rather than being used on a piece of artwork that was then bulldozed up a matter of weeks later."