Shares in NRW Holdings have surged after questions were raised in the West Australian parliament about the $2 billion Forrestfield Airport Link contract awarded to the company last week.
The construction company was handed a speeding ticket by the Australian Securities Exchange on Monday last week and again on Friday.
On Thursday, NRW Holdings and WA Transport Minister Dean Nalder announced the company had been selected to design, construct and maintain the link project, which will connect the eastern suburb of Forrestfield to Perth via the airport.
NRW shares jumped about 20 per cent in morning trade on Wednesday to 24.5 cents, compared to a close of 4.9 cents on February 12.
Mr Nalder was probed about the share price spike by opposition transport spokeswoman Rita Saffioti in parliament on Tuesday, saying he was notified about the contract winner on Wednesday afternoon last week.
"The advice I have is that all due process was followed," Mr Nalder said.
"The member is trying to suggest that someone internally within my department had something to do with it.
"If the member has any kind of evidence, I ask that she puts it forward and I would be more than happy to have it investigated.
"There was nobody in my office who was aware of it, as far as I know - nobody in my office at all."