A man charged with threatening a boy with a box cutter knife before robbing him of his phone remains in custody.

A 15-year-old boy was walking down a street in Cabramatta at 3pm on May 14 when a man came up behind him, pulled out a knife and demanded money.

The boy said he didn’t have any and the offender ran off with the boy’s smartphone.

Police searched a house on Anastasio Road in Liverpool on Friday and found a mobile phone and knife which were seized for forensic examination.

Elvis Tran, 21, was arrested at the house and appeared in Parramatta Bail Court on Saturday charged with robbery armed with an offensive weapon.

He did not apply for bail.

Bail was formally refused and the matter adjourned to Campbelltown Local Court on Wednesday.