Canterbury are set to announce the signing of NSW and Australia back-rower Tony Williams from Manly for the start of the 2013 NRL season.

Williams is believed to have agreed terms of a four-year deal that will reunite him with former Sea Eagles coach Des Hasler.

The giant 23-year-old joined Manly three years ago from Parramatta and knocked back offers from the Eels to return to the club where he began his career.

Williams is the first of Hasler’s 2011 premiership-winning squad to leave Brookvale to join him at Belmore.

The departure of Williams could help Manly keep hooker Matt Ballin, who is wanted by Canberra, and NSW fullback Brett Stewart.

Both players are off-contract at the end of the year.