Federal Attorney-General George Brandis has indicated it is highly likely Australia will head to a double dissolution election on July 2, saying he does not expect the Senate to pass two key pieces of Government legislation.

Key points: ABCC Bill already been rejected once by the Senate

ABCC Bill already been rejected once by the Senate Registered Organisations Bill has already been blocked twice

Registered Organisations Bill has already been blocked twice Senator Xenophon, along with other crossbenchers, want a number of amendments to the ABCC Bill

Parliament has been recalled early for an extraordinary sitting to debate the Coalition's bill to reintroduce the construction watchdog, the Australian Building and Construction Commission (ABCC), and the Registered Organisations bill, which aims to treat union leaders like company directors.

The ABCC Bill has already been rejected once by the Senate, while the Registered Organisations bill has been blocked twice.

Both pieces of legislation will be introduced on Monday, and both need to be passed for a double dissolution to be avoided.

Senator Brandis told Sky News he thought that was unlikely.

"I think it's impossible to imagine a set of circumstances in which the ABCC bill passes and the Registered Organisation bill doesn't," he said.

'July 2 election inevitable': Nick Xenophon

South Australian Independent senator Nick Xenophon, whose team looks set to take more seats in the Senate and challenge for a number of South Australian lower house seats at the upcoming election, told the ABC he did not expect the Senate to sit for the full two extra sitting weeks.

"I think it's unlikely to go through, I think it's almost inevitable that we'll have a July 2 election," Senator Xenophon said.

"There's the second reading stage, which is basically a vote to say 'should this legislation be further debated, should it be going into committee where you can consider amendments to the legislation?'

"I think it's touch and go whether it will even get through that first hurdle.

"I'll be voting for the second reading stages of that bill, I think it's important that we debate the bill, I'm sympathetic to a number of measures in the bill, but there needs to be some amendments."

Push for amendments to ABCC bill

Liberal Democratic senator David Leyonhjelm agreed.

"My guess is we'll probably go most of the week, but not next week and not the following week," he told Sky News.

Family First Senator Bob Day (R) with Senator Glenn Lazarus. Senator Lazarus says he will not vote for the ABCC bill in its current form. ( ABC News: Jenny Magee )

"I doubt it'll even get past the second reading and we won't even get into consideration of amendments."

Senator Xenophon, along with other crossbenchers, wants a number of amendments to the ABCC bill.

The South Australian wants changes to procurement policies to include requirement for locally produced goods to be used in construction projects.

Prime Minister Malcolm Turnbull and his Employment Minister Michaelia Cash have both said they would not consider amendments that would change the nature of the legislation.

That would mean Senator Glenn Lazarus's demands for a national anti-corruption body would not be considered.

"I certainly won't vote for [the ABCC] in its current form," Senator Lazarus told ABC Insiders.

"I've always been a campaigner for a national corruption and misconduct watchdog and I think it's a very relevant point.

"I don't think we need to be attacking one particular sector, we need to be covering all misconduct and corruption."