NEWCASTLE Labor MP Tim Crakanthorp has agreed to appear before a parliamentary inquiry to outline his claims he discovered a highly confidential government document in the electorate office he inherited from Liberal predecessor Tim Owen.

It comes only a day after he declined to give evidence at a scheduled public hearing of the inquiry, at which Mr Owen said he could not recall ever seeing the document and government MPs accused the Labor MP of ‘‘lying’’ and seeking to avoid giving evidence under oath about his find.

Mr Crakanthorp will now appear on Friday before the inquiry into city planning decisions, which must deliver its final report by March 5.

He had declined to appear before a Monday hearing of the inquiry, saying he was too busy.

But he also said he would appear at any subsequent hearing if necessary, and on Tuesday said he would ‘‘stick to that commitment’’.

He will be quizzed on his claims he found the leaked cabinet minute in the back of a filing cabinet in his office in December last year, having moved in after winning the October byelection.

‘‘I have been absolutely upfront in how I found this document in my office – the real question is why did Tim Owen have a confidential cabinet document in his office,’’ he said.

Inquiry deputy chairman and Greens MP David Shoebridge said it was good news after a ‘‘long’’ and ‘‘torturous’’ process to secure Mr Crakanthorp’s appearance.

‘‘I didn’t realise how busy he was,’’ Mr Shoebridge said.

The leaked cabinet minute sets out advice from Transport for NSW about potential routes for the light rail in the city, advising the best transport outcome would be to use the existing heavy rail corridor.

The government opted instead for a route down the corridor then into Hunter Street and Scott Streets, at a cost the minute suggests could run to $100million more.

The Department of Premier and Cabinet has referred the matter to the Independent Commission Against Corruption.

Mr Owen, who quit as MP after lying to the ICAC about accepting a $10,000 political donation from developer Jeff McCloy, said his former staff had disposed of all electorate records and triple-checked the office before it was handed over to Labor.

It is understood some of the staff have given evidence in closed sessions of the inquiry.