England star Wilkinson's departure to big-spending French club Toulon is expected to be confirmed in the next fortnight.
The Falcons, meanwhile, have moved to sign fly-half Jimmy Gopperth from Auckland-based Super 14 side the Blues on a three-year contract.
Gopperth, 25, has previously played for the Junior All Blacks, helping them win the Pacific Nations Cup.
He is a former Wellington Hurricanes player, starring in the Air New Zealand Cup for Wellington and North Harbour, and he was part of the New Zealand side that won the Under-21 World Cup in 2004.
Newcastle rugby director Steve Bates said: "Jimmy is an outstanding talent who has excelled at Super 14 level, and has the ability to really steer this team forward.
"We have been watching him closely for a number of months now, and have been impressed every time he has played.
"Jimmy is a fantastic goalkicker who links well, scores tries and leads the back-line in a very expert manner with his tactical kicking.
"There is quality about everything he does, he is at just the right age and having captained North Harbour last season, he has also developed the sort of leadership credentials which will be absolutely vital for us as a team.
"At this stage, his contract with us starts in November after the Air New Zealand Cup, but we are pushing hard to secure an early release from that so he can join us for pre-season in July."