A Senate inquiry will investigate the Albanese government’s decision to block Qatar Airways from almost doubling its weekly flights in Australia.

Nationals senator Bridget McKenzie secured enough votes on Tuesday afternoon to set up the probe as she accused the government of running a “protection racket” for Qantas.

It came as Prime Minister Anthony Albanese told parliament he did not know Qatar’s bid had been rejected when he met its Australian partner Virgin Australia three days later.

Under pressure from the opposition, Mr Albanese also said he did not speak to Qantas boss Alan Joyce about it.

“I once again confirm I did not speak to the former Qantas chief executive before a decision was made,” he said.

The government has been under pressure for refusing Qatar Airways’ bid to open 21 extra weekly flights into Sydney, Melbourne and Brisbane which could encourage competition in the market.

Treasurer Jim Chalmers was forced to defend Labor’s decision on Wednesday morning while speaking to breakfast television news programs – repeating that it was in the “national interest”.

The opposition’s motion to establish the inquiry passed the Senate on Tuesday afternoon by one vote.

Its scope will include “any proposals received in the past 12 months for additional services to Australia’s major airports”, which could potentially encompass other airlines.

The committee – comprised of three opposition members, two government members and two crossbenchers – will hand down its report in October.

Senator McKenzie accused the government of trying to protect Qantas, which had lobbied against more flights for Qatar Airways.

“Who is the government really protecting when it says this decision was in the national interest?” she said on Tuesday.

The Senate has ordered the production of documents, giving the government until next week to table them or explain why they’re being withheld.

The government has not yet explained why the decision was in the “national interest”.

Industry experts and the ACCC said allowing more flights would encourage competition and potentially bring down ticket prices for customers.

Meanwhile Mr Joyce announced on Tuesday he would retire early in the wake of a political furore over the airline’s profits and service.

The outgoing chief executive advised the Qantas board he was bringing forward his retirement by two months to “help the company accelerate its renewal”.

• Related story: Inside Alan Joyce’s turbulent years leading Qantas

Vanessa Hudson takes up the role of managing director and group chief executive on Wednesday.

Mr Joyce’s decision came after a horror week for Qantas marked by a Senate grilling on delays, and warnings that the airline faces a possible $250 million fine.

The Australian Competition and Consumer Commission is taking court action after Qantas allegedly advertised tickets for flights that had already been cancelled.

The company is reviewing the allegations and has acknowledged its standards “fell well short” as the airline emerged from the COVID-19 pandemic.

Last month Qantas announced a record pre-tax profit of $2.47 billion for the past financial year, after recording a loss of almost $2 billion the previous year.

Soon after, it came under pressure to pay back the money it received from the federal government at the height of the pandemic.

It was given $2.7 billion from taxpayers, including $900 million from the JobKeeper program.

-with AAP