The finance minister, Mathias Cormann, says the Liberal partys preference deal with One Nation was intended to minimise losses in the Western Australian election. Photograph: Mick Tsikas/AAP

One of the architects of the Liberal partys preference deal with One Nation in Western Australia, the federal finance minister, Mathias Cormann, has defended the controversial arrangement, and he has refused to rule out a future preference deal at the federal level.

Cormann told the ABCs Insiders program on Sunday the preference deal, which put One Nation ahead of the National party in some areas, was negotiated in an attempt to put a floor under the Liberal partys declining primary vote, which he said was as low as 29% in internal party polling.

The strategy failed to deliver the desired result and Labor has swept to power in WA courtesy of the weekend election, with Mark McGowans new government currently tipped to pick up 40 seats in the state parliament.

The latest count in WA puts the negative swing against the Liberal party at 15.7% and the positive swing to Labor at 9.7%. One Nation, which had been polling in the double digits according to published surveys, polled under 5% in the final state wide count.

Cormann on Sunday defended the controversial preference arrangement with One Nation, arguing it would make a positive difference for the Liberals in a couple of seats and was justified on the evidence before the partys state executive at the time they made the decision.

Anticipating backbiting and bloodletting in his home state, Cormann noted the state executive had approved the deal unanimously.

If we wanted to minimise losses, maximise our chances of holding on to seats, we needed to be able to source preferences and, clearly, these werent going to come from Labor and the Greens, the finance minister told the ABC on Sunday morning.

He refused to rule out further cooperation at the national level, saying these are judgements that will be made at the right time.

Cormann said the Liberal party would assess the factors behind the weekend rout in WA.

I am personally very comfortable that Labor and the Greens obviously should always be towards the bottom of our ballot paper, Cormann said.

But the deputy prime minister and Nationals leader, Barnaby Joyce, was unequivocal in his negative assessment of the preference deal, which he categorised on Sunday as a mistake.

He said the preference deal had two problems: the Liberals had overestimated One Nations electoral support and had confused their constituency.

Its in the Liberal partys interest to be close to the National party and its in the National partys interest to be close to the Liberal party, and its in both our interests not to confuse anybody else, Joyce told ABC radio.

I think the Liberal party should preference the Liberal party and the Nationals should preference the Liberal party.

They are separate parties, they talk to different constituencies, but people see them as a team and we should stick to that idea.

It hasnt been a good day in the office and there are a lot of questions that need to be asked.

You rate your preferences in the order of people you would like to run the country.

Joyce noted the One Nation campaign had been a bit of a shocker but the Nationals had done well in farming regions and would likely hold their at-risk seats in the mining regions.

The One Nation leader, Pauline Hanson, was also walking away from the preference arrangement on Saturday night.

Doing the deal with the Libs has done damage to us, in all honesty. It was a mistake, Hanson said. We are really going to have to have a good look at this because all I heard all day leading up to this election was why are you sending your preferences to the Liberal party?

Hanson suggested the problem stemmed from doing a deal with a major party leader past his use by date. It wasnt One Nation. I think it was Colin Barnett people did not want Colin Barnett.

Its like when youve got milk in your fridge and its starting to go sour, you throw it out, and thats what they should have done.

Cormann was asked about criticism from the National veteran Ron Boswell last week that the Liberal party was being too accommodating to Hanson since her return to the federal scene last year.

He rejected the Boswell critique, saying the government had no choice other than to develop a positive relationship.

In the Senate, if we want to get important legislation through for our country, in our national interests, we have to deal with the people that have been elected by the Australian people into the Senate, Cormann said Sunday.

We have to work with One Nation senators as we have to work with Nick Xenophon Team senators, as we have to work with the Liberal Democrats and Cory Bernardi and others represented in the Senate.

That is our duty and responsibility to do that.

Cormann also played down local controversy about WAs share of the GST as a factor in the result.

This was a big issue in the lead-up to the last federal election and we won 11 out of 16 seats, and 54.7% of the two-party preferred vote, the finance minister said.

This is an issue in WA, no doubt about it. By the same token, we have to be realistic on what a national government can do in relation to these sorts of issues and the timetable is determined by what happens with the GST sharing arrangements moving forward.

There is a flow-through effect, principally from the prices for iron ore and the royalty revenue that is generated on the back of iron ore exports.

That will play out over the next few years and there is an expectation in the not too distant future, WAs share of the GST will start increasing again and, if and when that happens, there are certain options available where the floor can be established without actually taking money away from any other state.

That is the way it should happen.

Federal Labor argued there were substantial federal implications from the result, with frontbenchers arguing the recent Fair Work Commission decision on penalty rates had hurt the Liberals and One Nation both supporters of the proposed cut.

Bill Shorten took to Twitter to deliver his verdict and to criticise Cormann for failing to rule out future preference deals with One Nation.

Read more:

Liberal party defends preference deal with One Nation after WA election loss - The Guardian