Patrons at the Allianz Sydney Football Stadium would be in “frightening” danger if it had to be evacuated, a New South Wales parliamentary inquiry has heard.

It would take 24 minutes to safely empty the stadium at full capacity compared to the global recommendation of eight minutes, according to Sydney Cricket Ground trust chairman Tony Shepherd.

He gave the evidence to a joint parliamentary committee, which is scrutinising the government’s controversial billion dollar splurge to rebuild Sydney stadiums.

“In an emergency, patrons face the very real prospect of very serious injuries or worse in the rush for exits,” Mr Shepherd told the inquiry at a hearing on Monday.

God alone knows what would happen in an emergency.”

He blamed a fundamental flaw in its outdated design, saying it could not be fixed by refurbishment.

It was “quite obvious” that stadiums are “a good target for people trying to make terrible mischief”, the trust chairman said.

“The potential consequences we’ve been advised of by a series of experts are frightening. And I think they are too frightening to ignore.”

In his evidence Mr Shepherd, who supports the rebuild, also revealed the stadium has just 48 women’s toilets when it should have 335.

He said the crowd has an average gender split of 30 per cent women, compared to almost 50-50 at the SCG.

Allianz is also far short on wheelchair accessible spaces, with 28 spots instead of 400.

Parramatta Stadium rebuild

A key claim supporting the business case for a new Parramatta Stadium in western Sydney was never agreed to by the NRL, the inquiry heard.

The business case anticipated that 30 NRL games would be played at the venue.

But the sport’s second-in-command on Monday said the league never agreed to that.

“We haven’t given any commitments of that nature,” NRL chief operating officer Nick Weeks said.

“Where our clubs play their matches will be a matter for clubs to determine.”

Infrastructure NSW gave evidence later on Monday that it was a 30-year projection.

Department adviser Janett Milligan said the figure did not include the burgeoning women’s league and it was a conservative estimation.

Labor committee member Lynda Voltz accused the government of inflating figures to justify their stadium spend.

“This is what the government has done – they’ve over-inflated figures. The NRL says they didn’t provide these figures,” Ms Voltz told AAP.

“Where did 30 games come from if the NRL didn’t provide them those figures?”

NSW Sports Minister Stuart Ayres said it’s up to clubs to decide where they play.

“Government has no role in directing which events are held where,” he said.

“We’re investing in the best facilities to ensure Sydney and NSW is the No.1 destination for sport and major events.”

Infrastructure NSW said the Parramatta Stadium rebuild was due to be delivered under budget at almost $330 million, below the projected $360 million.

Its construction is on time, to be completed in March.

The government originally planned to knock down and rebuild Parramatta, Allianz and ANZ stadiums at a cost of well over $2 billion but has since scaled back the scope of the works.

Premier Gladys Berejiklian in March backflipped on the demolition of ANZ Stadium, choosing to instead refurbish the venue at a cost of $810 million – saving $500 million.

The total stadium spend now stands at $1.8 billion for the three venues.

-with AAP