Kristina Keneally has been caught out campaigning against her own party's record by taking aim at a decision to close a local Medicare office that was made by a previous Labor government.

Labor's star candidate has been surging in the polls for the Bennelong byelection in a seat vacated after incumbent Liberal John Alexander was forced to resign after being caught out in the citizenship scandal.

The former NSW premier has focused heavily on claimed government cuts to Medicare, which were a successful but controversial opposition tactic at last year's federal election.

"The Liberals in 2015 shut down the [Eastwood] Medicare office, making it harder for people in this community to get their Medicare claims sorted," she said at her opening press conference last Wednesday. "That's what happens when the Liberals come in government, they cut services."