A London authority said on Wednesday it had imposed "temporary measures" around a new mural by British street artist Banksy, after it was defaced within days of appearing.

Islington Council, in north London, said it had erected fencing, camera surveillance and ordered visits by community officers to manage on-lookers to help protect the artwork.

The stencilled mural of a person having spray painted tree foliage onto a white wall behind a leafless tree, appeared on a street near Finsbury Park this week.

The enigmatic artist appeared to confirm his role in the creation, posting before and after pictures of the transformed wall on Instagram on Monday.

But following a flurry of media reports and public attention, it had by early Wednesday been defaced. Images shared on social media showed two streaks of white paint strewn across the bright green artwork.

"It's sad to see the piece has been defaced," an Islington Council spokesperson said.

"We are discussing future solutions with the homeowner, to enable everyone to enjoy the artwork while protecting it, the tree, and the surrounding area.

"We're also in the process of installing a CCTV camera."

In December, police arrested two men on suspicion of theft and criminal damage after a Banksy artwork was removed from a south London street corner within hours of appearing there.

That installation, a traffic stop sign covered with three aircraft resembling military drones, emerged at an intersection in the Peckham neighbourhood.

Witnesses filmed it being removed by a man with bolt cutters, with the help of another man.