Staff in the Department of Finance went home on the night of a budget to see what measures had been announced by Government on TV, the €5m Oireachtas Banking Inquiry was told.
The comments from Canadian finance official Rob Wright come as it has emerged that the inquiry is to again write to the European Central Bank to demand documents relating to the Irish crash. This is after the ECB formally refused to appear before the inquiry.
The ECB is one of a number of institutions that the inquiry is writing to seeking documents for the "nexus stage" of the inquiry, which will now not begin until after Easter.
This means many of the key witnesses, including former Taoisigh Brian Cowen and Bertie Ahern, former ministers, officials and senior bankers, won't be heard of before then.
The inquiry met for two hours in private yesterday where members raised the possibility of axing a number of potential witnesses in order to hasten its work programme. At the public hearing, Mr Wright said he found it "incredible" that staff in the Department of Finance were completely out of the loop as to what was in the Budget during the last decade.
He told the 11-member inquiry team he was in Dublin working on the report when the Budget was announced.
"People in the Department of Finance went home on Budget night to find out what was in the Budget," said Mr Wright, who was also known as Canada's deputy finance minister.
"Why didn't they know? They were in the Department of Finance. I found that incredible."
There was an election dynamic to the Department of Finance in the years coming up to the crash, he said. Mr Wright agreed figures were run on election cycles, and said he uncovered little written formal advice between public servants and Government at the height of the crash amid fears it might have to be released under Freedom of Information requests.
Mr Wright was being pressed on his 2010 report into the failings of the Department of Finance in the run up to the crash, which stopped short of saying it was not "fit for purpose".
Mr Wright said had he been in place in Ireland he would have "pressed the red button" in terms of sounding the alarm as to the dangers in the economy.
He said that, within the department, there was very little written advice at all given to political masters by officials.
The Freedom of Information Act was cited as "the most dominant reason" behind the lack of information deficit, he revealed.
Mr Wright also highlighted the lack of an "independent voice" to restrain the economy because we are part of the Euro.
"We have an independent monetary policy in Canada. The Governor in Canada has great authority. Here, you do not have someone independent to restrain the economy when it needs to be. That has to be you, the politicians," he said.