Pike River Coal's safety practices have been called into question at the start of an inquiry into the mining disaster that killed 29 workers.
The bodies of the men remain in the mine following a series of explosions that began on 19 November last year.
The Royal Commission headed by Justice Panckhurst began at the Greymouth District Court on Monday and will try to establish what happened at the West Coast mine.
State-owned Solid Energy chief executive Don Elder was the first to give evidence and has been called as he is an expert in mining coal in the Brunner seam where the Pike River mine operated.
Dr Elder said the Pike River Coal project was overly optimistic, and production and financial problems had the potential to create many safety risks.
He told the inquiry he never believed Pike River Coal Ltd was likely to achieve production targets and that this was likely to result in major financial problems.
Dr Elder said three factors at Pike River had potential to generate safety risks that would have been largely unique to the mine at the time of the explosions.
They were: difficult geological conditions likely to cause frequent surprises, an uncommon hydraulic mining method that introduced new risks, and the company's prolonged production and financial under-performance.
Dr Elder said the Pike River mine development was along lines that Solid Energy would not call good industry practice.
However, lawyer Stacey Shortall, who is representing Pike River Coal chief executive Peter Whittall and other managers, pointed to Mr Whittall's 30-year mining experience and challenged Dr Elder to back up his statements.
Dr Elder said it was an industry view that a company under financial pressure had to pay extra attention to safety.
Earlier, a lawyer for the Royal Commission said there should be no early judgement as to any fault which led to the tragedy.
In his opening address, James Wilding said an inquiry such as this had "the potential to occasion serious harm to the reputation of those whose actions are under scrutiny."
"Because of that, it is important that everyone reserve judgement until those the subject of serious allegations have had a proper opportunity to be heard," he said.
The focus in the first two-week phase of the Royal Commission is the context of the event, including the regulatory environment for mining and the design and development of the Pike River mine.