A 74-year-old Bruce man has been charged with five offences in relation to sexual assault incidents alleged to have occurred in Canberra in the late 1970s.

Police said on Tuesday that in November an online report was made relating to historical sexual assault allegations, allegedly committed by the man against a primary school-aged girl the man was regularly babysitting.

They allege the man took the girl to nudist gatherings at a Canberra pool, that he bathed with the girl at his home and that he committed acts of indecency.

The 74-year-old man has been summonsed to appear before court on September 2 to face five charges of indecent assault on a female.

Police said there was no time limit to report this type of crime.