A 25-year-old man who raped a woman who had fallen asleep on a couch after a party at an inner Sydney share house has been jailed for at least two years and three months.

Scott Harry Richardson, who is from England and was working in Australia, had not met the woman, 23, before she was invited by her boyfriend to a small "impromptu party" at his Redfern apartment in December 2015.

Scott Harry Richardson, 25, was found guilty of rape during an impromptu summer party at his flat. Credit:Facebook

The woman, an American backpacker who had been in the country for about a month, fell asleep on the lounge room couch in the early hours of the morning.

While she was sleeping, Richardson removed her shorts and underpants. The woman woke to find him on top of her raping her.