The state's unions have banded together to challenge the government's transparency laws, which prohibit them from running political campaigns of more than $10,000 without first balloting their members.

Under the law, for the ballot to be valid, at least half of the union's membership must vote yes.

The High Court is expected to set down a hearing date for the matter in the next two weeks.

It comes as the Together Union has been forced to defend the eight-month-old Working for Queenslanders corporation, and its funds, which was established before the union transparency legislation was passed in June last year.

In a widely publicised move, the Together Union, after “talking with members” transferred $7.5 million, raised from a public sector defence fund to the Working for Queenslanders trust corporation, in order to circumvent the June legislation.

In response, Jarrod Bleijie amended the transparency laws last August to include "anti-avoidance" provisions "to cover entities associated with an industrial organisation".

Together Union secretary Alex Scott said his organisation had done nothing wrong and each step along the way had been made public.

“The union was looking at the best way to protect the public sector defence fund to continue to operate the way that members had determined it should and the company was established as a result of that,” Mr Scott said.

“We've completely cooperated with the industrial inspectors who have asked questions about the expenditure and we will continue to abide by the disclosure laws for both state and federal activity and we will continue to abide by the legislation.

“But there is nothing secret in the process, the company is registered and it abides by the corporations laws and clearly we will make sure we abide by both state and federal legislation. There is no secret, the company is new and is going through a range of process changes, but nothing significant.”

Unions would not be able to establish a corporation like Working for Queenslanders under the current legislation.

Queensland Council of Unions President John Battams said it was the restrictions on how unions communicated with its members and the public which was at the crux of the High Court challenge.

“We proceed with these things when we have advice from senior counsel, that we have a better of even chance of winning,” he said.

“You should not be able to restrict or constrain people from being able to communicate freely with the public in a democratic society.

“We believe we are on very solid ground with this challenge.”

Attorney-General Jarrod Blejie said the government will “fight any attempts by union bosses to take power away from their members”.

“We put these transparency laws in place to empower the hardworking, grassroots members of industrial organisations and give them a chance to have a say on how their membership fees were being spent,” he said.

“Unfortunately, the union bosses want to spend a lot more of their members' money to fight to protect their own empires.”

Mr Battams said the challenge would be funded "through contributions from unions and supporters".