WikiLeaks founder Julian Assange will appear in a British court on Tuesday in a second attempt to win bail after he was arrested over allegations of sex crimes in Sweden.

The 39-year-old Australian makes his second appearance at court in London since his detention one week ago under an international warrant sent out by Sweden.

His arrest came shortly after his whistle-blowing website started releasing tens of thousands of leaked US diplomatic cables, in a move that has infuriated Washington.

Supporters of Assange and his site are expected to protest outside the City of Westminster Magistrates Court, amid a growing backlash against his arrest.

Swedish authorities want to question Assange over allegations of rape and molestation made against him by two women in relation to incidents during his visit there in August.