Councils could get the green light to run their own bus companies or force firms to bid for the right to run routes under plans to save services.
Economy Minister Ken Skates said de-regulation of bus services in the 1980s had been "an abject failure".
The Welsh Government is planning a new law to reverse the free market reforms.
But bus operators claimed that "simply focusing on the regulatory regime will not deliver the quicker journeys that will benefit passengers".
Until the 1980s much of the British bus network was run by publicly-owned companies with local monopolies, until services outside London were opened up to competition by Margaret Thatcher's Conservative government.
Since then, many of the less profitable routes have lost their services.
In Wales, passenger bus journeys have fallen from 125.3m in 2007-08 to 99.9m in 2017-18.
"It's clear that the free market model simply does not work," Mr Skates said.
However, ministers will not force councils to use the new powers, and no new money is expected to be announced alongside the law.
The Bus Services Bill will provide councils powers to set up franchises - meaning companies would have to bid for the right to run bus services on certain routes - similar to how buses are run in London.
The measure could be used to eliminate competition between bus firms running along the same routes, seen within government as duplicating services and potentially adding to pollution.
The aim is to boost services, with companies potentially required to run less lucrative routes as part of any agreement.
Currently, although companies can be subsidised to run unprofitable services, they are largely free to choose what routes to serve.
First Cymru, which runs services in south and west Wales, has claimed franchising would act as a break on investment, while local-authority owned Cardiff Bus was worried that it could lose its entire market to a larger company.
One local government body, the Public Transport Consortium, warned franchising "cannot resolve the fundamental issue which is a lack of [council] funding".
In a major change to the current rules, councils working individually or together could also run their own bus firms to fill gaps in provision.
The move would reverse a law dating from Margaret Thatcher's government that barred councils from starting bus services.
De-regulation in the 1980s saw many councils sell off their bus services, with some exceptions. Both Cardiff Bus and Newport Transport are owned by their respective councils, but operated at arms length.
Other measures in the bill include powers to improve the sharing of up-to-date information for passengers.
Councils could also strike partnership schemes with bus firms, allowing them to agree how services can be improved.
Measures like the enforcement of bus lanes could be introduced in agreement with operators providing services at certain times and frequencies.
Mr Skates said: "This legislation isn't a silver bullet - it has to go hand in hand with our investment in Metro systems and plans to tackle congestion."
He claimed it would be a "vital toolkit that can help us deliver on our ambition for an integrated and seamless public transport system".
More than £220m of Welsh Government cash goes into services, through subsidies and other schemes like the concessionary bus pass.
Source: BBC