Mr Walley, who will speak at the conference today, felt any policy changes would be impossible until the Government acknowledged that the decline of the manufacturing sector was a problem.
"There's been any number of surveys of exporters this year and the bottom line is exchange rate. The Government's in denial."
Opposition parties said 40,000 manufacturing jobs had been lost since 2008, and pointed to further evidence of a crisis yesterday, with the BusinessNZ Performance of Manufacturing Index showing the sector had been in decline for four consecutive months.
Finance Minister Bill English has acknowledged times are "pretty tough" for the sector but said he did not believe it was in crisis.
Mr Walley said the Government was too narrowly focussed on balancing its books by 2015, and needed to invest more in manufacturing now to avoid a long-term trades drain.
"This is like a slow-motion train wreck. If people start to see some effort and building towards a structural solution, then they'll start to take different decisions."
The Government has not been invited to the summit, which is expected to host around 70 people.