Newcastle could lose centres Jamie Noon and Mathew Tait to England's World Cup squad while Toby Flood and Jonny Wilkinson are also likely to be in the squad for France.
Director of rugby John Fletcher said: "Mark has been a supremely consistent performer for the club during his time with us.
"He had planned to return home to New Zealand at the conclusion of this season, but with so many of our inside backs expected to be involved in the World Cup he has agreed to stay with us until they return.
"That is a massive plus for us during a time when we expect to have a number of players away on international duty.
"We know exactly what we are getting with Mark - a very experienced player who leads by example and will be a vital part of our plans during the early part of the season."
Fletcher confirmed that Mayerhofler will not play again this season after undergoing surgery for a long-standing shoulder injury.
He said: "The operation had been scheduled for a while and we were just waiting for the end of the Six Nations to get it done.
"What it means is that he will now miss the remainder of the current season, but will be back firing on all cylinders for the big kick-off in September."
Mayerhofler has made 89 appearances for Newcastle, scoring eight tries, in his five seasons at the club.
The Kiwi was part of the Crusaders side which won the Super 12 title three times in successive seasons between 1998 and 2000.
He joined the Falcons midway through the 2002/3 season and signed a new two-year deal in the summer of 2005.
Capped six times by the All Blacks, Mayerhofler has also appeared for the famous New Zealand Maori side and the New Zealand Barbarians.