A man and a woman will appear in court on Wednesday to face charges of planning to carry out a terrorist attack in Sydney.

The 19-year-olds, who have been in custody since they were arrested early last year, will appear in Central Local Court.

They face charges of ‘conspiracy to do an act, or acts in preparation for, or planning, a terrorist act or acts’.

When the duo were initially arrested, the man charged with collecting documents likely to facilitate an attack, and the woman with recklessly possessing documents and other things connected to an attack.

The new charges follows an extensive investigation by officers from the NSW Joint Counter Terrorism Team.

The charge carries a penalty of life imprisonment.