An inquiry into Transport Minister Gerry Brownlee and his deliberate breach of airport security is unlikely to be completed before the election.
Mr Brownlee and two of his officials side-stepped security in Christchurch Airport on July 24, avoiding scanning equipment by entering a gate lounge through an exit door.
He offered his resignation to Prime Minister John Key, who refused it on the basis that he had been a good minister.
The Civil Aviation Authority is investigating. The Herald understands that while Mr Brownlee has already been spoken to, several interviews still have to take place.
A report then needs to be written and reviewed. It is understood that it is unlikely to be finished before the election.
Civil Aviation Authority director Graeme Harris said the investigation was ongoing.
"The CAA will not make any comment on the investigation or speculate on the possible outcome while it is still underway."
Meanwhile, there is still no indication when former Malaysian diplomat Muhammad Rizalman bin Ismail will be back in a New Zealand court to face charges of burglary and assault with intent to commit rape.
Rizalman was reportedly released from psychiatric care last month. But a spokesperson from the Ministry of Foreign Affairs and Trade said there was no update on when he might return to New Zealand.
There was no indication whether he might be back before or after the election, the spokesperson said.
The incident embarrassed the ministry. Mixed messages to Malaysian officials led them to believe Rizalman returned to Malaysia under diplomatic immunity with the blessing of the New Zealand Government.
New Zealand and Malaysia have since committed to Rizalman's return.