Mr Oaten said Martin Tod and Jackie Porter were disloyal. Both have called on Mr Clegg to stand down after the poor results from the European and local government elections.
He said: “I totally disagree with Martin and Jackie calling for Nick to resign. I am sorry that they have both chosen to be disloyal to their leader in this way. These were very tough elections but Nick did the right thing to take on UKIP and to stand up for both the Coalition and our pro-European views.
“Sometimes in politics you must stick to what you believe in even if it’s unpopular. And sometimes as local candidates you should back your leader during the tough times."
Mr Tod was the Lib Dem parliamentary candidate in 2010. Ms Porter has been chosen to fight the seat in 2015.
Neither was today available for comment.