Taxi plate owners in Western Australia will be able to apply for assistance payments from Monday in a bid to help ease the pain caused by deregulation.

Plate owners will be sent letters from tomorrow inviting them to apply for transition assistance payments, after the Legislative Assembly passed a bill which included the first stage of the Government's taxi reforms.

The bill, facilitating the $20,000 per plate payments, still needs to be passed by the Upper House, but that is expected to occur in the next few weeks.

The assistance comes after the Government moved to legalise ride-booking services, such as Uber, which have dramatically eaten into the market share of taxis in the past two years.

Transport Minister Dean Nalder has set aside $20 million for the assistance payments while a $6 million hardship fund is also being created.

Mr Nalder left the door open to further help down the road, saying a plate buyback scheme was one of the options being considered when further reforms are settled on by November.

But he rejected an amendment moved by Labor which would have given him the power to launch a buyback scheme, saying its proposal was insufficiently detailed, and he did not want to hold up the assistance payments.

The Government also rejected Labor's attempt to dramatically increase the size of the payment, to $162,500 per plate, which it claimed was needed because the proposed payout did not adequately reflect the industry's suffering.

Size of payout widely criticised

The $20,000 payments have also been rejected as inadequate by many in the industry and members of the Liberal Party's own backbench urged the Government to provide more money during debate on the legislation.

"It is a starting point but it is nowhere near enough," Liberal Whip Tony Krsticevic told Parliament.

"I don't know what an appropriate level of compensation is, but I do know the industry has suffered a lot, the value of plates has gone down a lot and I believe that assistance should adjust for those changes," he said.

Labor's transport spokeswoman Rita Saffioti described the measures as "woefully inadequate".

"It will now be an issue we take to the election," she said.