Police publicly released a CCTV image of a motorist who they said may be able to help with the investigation into the Peninsula Art Auction banner on Norwich Quay.
A spokesperson said on Thursday the woman has now come forward and is assisting police with their inquiries.
"The owner of the banner has been advised."
The banner was stolen on October 5 and the replacement was vandalised on Sunday.
The auction fundraises for Lyttelton Primary School by selling donated art pieces.
It will be held at the school from November 1-2.
Event organiser Taff Gilvray said the theft and vandalism was disappointing. But she was overwhelmed by support from the community.
"We’ve had so many people reaching out with great things to say and we've had local businesses offering to replace the sign. We had another business who offered us free electronic signage,” she said.
A group from the Lyttelton Scouts repaired the banner on Monday in the pouring rain without being asked.
The auction is held every two years and has raised about $500,000.
It raised $70,000 in 2023. This year more than 250 pieces from 100 artists will be auctioned off.
Two sketch drawings by the late Lyttelton artist Bill Hammond will be auctioned, as well as pieces from Jason Greg and ceramics from Nicola Shanley.
"We're pretty lucky with our local talent,” she said.
•If you recognise the woman or have information that could help with the police investigation, call 105 or Crime Stoppers on 0800 555 111 and use reference number 251013/6745.
