WA Labor leader Mark McGowan faced voters at a Sky News People's Forum ahead of the state election on Saturday.

Sixty-three per cent of the forum said they are now more likely to vote for the state Labor leader, while 28 per cent are still undecided and 9 per cent are less likely.

Mr McGowan spent Thursday night answering questions by undecided voters solo, after WA Premier Colin Barnett pulled out of the event.

Issues surrounding the GST, drug usage, renewable energy and education dominated the event.

GST has been a major talking point for both political parties with the community calling for a change to the way GST is distributed.

Mr McGowan told the audience WA Labor would 'fight hard' to get a better GST formula for the state.

'We need a better share of the GST pie in Western Australia,' he said.

'We clearly are being not treated fairly I think that everyone accepts that Tasmania and the Northern Territory, South Australia at time may need a bit of support but the situation where by western Australia goes down to 30 cents in the dollar is clearly completely and utterly unacceptable.'

The issue of TAFE fees was also highly debated at the forum, with Labor vowing to freeze the current TAFE fees for the next four years.

'One of the things we are committed to is freezing TAFE fees,' he said.

But Mr McGowan did concede there wasn't a whole lot he could do to cut fees.

'There's been a 500 per cent increase in the cost of some TAFE courses over the last couple of years... I can't undo everything because the financial situation is so difficult.'

The party's policy of rehabilitation for drug users went over well with most audience members, with communities calling for more to be done to curb drug usage in youth.

'Our plan is based upon on addressing demand and addressing supply. We have announced heavier penalties for traffickers which involves life sentences,' he said.

'On top of that we've announced 100 police officers will be dedicated to the Meth Boarder Force.

'The third thing is addressing demand. We are taking existing prisons and converting them to rehabilitation prisons so if you go into prison you can get immediately 'triaged' into a meth rehabilitation prison where there's proper services and support.'

Earlier, WA Labor announced it will get the state's budget back in surplus by 2019/20, but will make only a small dent in debt tipped to hit $41 billion, after releasing its election costings.

The costings, ticked off by two former public servants, estimate a capital spend of $2.8 billion - not $5 billion as widely estimated - that can be easily covered by $3 billion of sources including federal funds not yet guaranteed.

However, Labor has not included spending beyond the four-year forward estimates, with stage one of its Metronet project alone costing $2.95 billion.

Labor shadow treasurer Ben Wyatt and finance spokeswoman Rita Saffioti released the costings, done by independent assessors and not Treasury, on Thursday.

Rather than hand Treasury its costings details, the opposition enlisted two former senior public servants, including former public sector commissioner Mike Wood, to run the ruler over its numbers.

The Liberal government has criticised the ALP's decision not to have Treasury do the costings and to reveal them just two days before Saturday's election.

'This is a deliberate attempt by Mark McGowan to escape scrutiny because he cannot fund his $5 billion worth of promises,' Premier Colin Barnett told reporters on Thursday morning.

Treasury costings of Liberal election promises released on Wednesday show they amount to almost $2.6 billion, which is lower than initial estimates.

It was also revealed Royalties for Regions spending in country areas would be reduced from $1 billion a year to $800 million in 2018-19 and 2019-20, which has angered the Nationals.

AAP