North Shore MP Felicity Wilson's political future has hit another hurdle with her rival lodging an 11th hour appeal against her preselection with the NSW Liberal Party executive.

Ms Wilson narrowly survived a challenge to her career last week when she won a razor tight preselection battle for the North Shore seat against former Liberal staffer Tim James by one vote.

Felicity Wilson won the preselection ballot by one vote.

But Mr James has now followed through on his threat to challenge her victory, with Liberal party sources confirming he had formally appealed the verdict through the party's disputes resolution process on Monday.

In an email to Liberal preselectors on Tuesday, Mr James said he had been "advised by many, including independent legal counsel and senior counsel, that there are fundamental flaws and failures affecting the declared result last week."