A service station attendant was stabbed while complying with demands of two teenage girls who allegedly held up the north Queensland store at knifepoint.

A service station attendant has been stabbed in the shoulder during a north Queensland armed robbery allegedly committed by two teenage girls.

The girls, aged 15 and 19, walked into the store at Kirwan in Townsville just after midnight and demanded money while armed with a knife, police say.

One of the teenagers then allegedly stabbed the attendant in the shoulder, despite their demands being met.

The attendant was taken to hospital with non-life threatening injuries.

Police say both girls ran from the store but were quickly caught.

They have each been charged with entering a premises to commit an indictable offence and armed robbery.

The 19-year-old will appear in Townsville Magistrates Court on Friday, while the younger girl will be dealt with under the Youth Justices Act.