King has been at Old Trafford since 2008 and has spent time on loan at Preston North End, Borussia Monchengladbach and Hull City in recent seasons.
His representative, Jim Solbakken, has revealed that there is plenty of interest in King, who has been linked with a permanent move away from the Red Devils due to their current wealth of attacking options.
"I have discussed attacking options with Newcastle. There are many clubs who are interested in Joshua King but he is where he should be," Solbakken told VG.
"He could have joined many clubs during the summer but got confidence in the Manchester United organisation."
Oslo-born King has been capped twice by Norway at senior level after debuting earlier this year.