Former city Comptroller John Liu still owes the city more than $525,000 in campaign fines — even as he plows ahead with his latest run for office.

Liu, who’s seeking to unseat state Sen. Tony Avella (D-Queens), was hit with the sky-high fines for hanging campaign posters illegally during his successful 2009 run for comptroller.

But he has paid back less than $22,000 and has a lawsuit pending in Manhattan Supreme Court challenging the fines

“While we cannot comment on a pending legal proceeding, we will continue to challenge these unfair fines until they are overturned,” said his campaign spokesman, James Freedland.