NEWRY, Northern Ireland (Reuters) - Charges of historical sex offences against the former leader of Northern Ireland's Democratic Unionist Party (DUP), Jeffrey Donaldson, can proceed to trial, a judge ruled on Wednesday after prosecutors presented further charges.

Donaldson, 61, stepped down suddenly as head of the British region's largest unionist party in March after the DUP said he had been charged with allegations of an historical nature. He is one of Northern Ireland's best-known politicians.

Donaldson, who appeared in court on Wednesday, faces 18 historical sex offence charges, including one count of rape. Prosecutors had originally brought 11 charges against him.

The charges include 13 counts of indecent assault on a female child and four counts of gross indecency towards a child. The charges relate to two complainants and the events allegedly took place between 1987 and 2008.

Donaldson's wife, Eleanor, also appeared in court and faces five charges, including aiding and abetting rape. She had initially faced four charges.

Judge Eamonn King said he was satisfied that both have a case to answer. He asked them if they understood the charges, which they confirmed. No pleas were taken.

The matter will be back before the court on Sept. 10 when the trial will be scheduled.

(Reporting by Amanda Ferguson anfd Padraic Halpin; editing by Mark Heinrich)