Manager Liam Daish is a keen admirer of the 25-year-old and has brought him to Stonebridge Road on a free transfer.
"Neil made a big impact during his time at Woking," Daish told the club's official website.
"Glenn Cockerill rated him very highly, and Frank Gray wanted him to go back for pre-season this summer, so we have done well to bring him to the club.
"He will bring a physical presence to our midfield and is capable of getting his name on the scoresheet."
Barrett started his career at Chelsea alongside Fleet's Danny Slatter and England skipper John Terry before making a switch to Portsmouth in 2001.
He went on loan to Dundee in January 2004 and eventually joined them on a permanent deal.
Source: http://www.confguide.com/newsArticle.do?id=6678