The 20-year-old, whose father Mark is a former Brighton keeper and currently under-21 goalkeeping coach at Stamford Bridge, will stay with the Exiles until April 16.
Beeney initially moved to Rodney Parade in mid-January and has made four appearances so far
County boss Warren Feeney told the club's official website: "I'm delighted that Mitchell has chosen to extend his stay with us
I am very pleased to have him on board
"The whole squad has taken to Mitchell and I want competition for places
I have three very good goalkeepers in the squad at present and I want to keep that competition for places, as it keeps everybody on their toes.
"I have been very impressed with his performances so far
He comes from a very good footballing upbringing at Chelsea and he is a player that I am delighted to have at my disposal."
Source : PA
Source: PA