It's finally happened. The Queensland parliament has struck a blow for the ordinary citizen against our political parties' insatiable appetites for power and influence.

It has passed a new Electoral Act which, among many things, introduces optional preferential voting in time for this year's state election.

Gone is a requirement voters record preferences next to every candidate on the ballot paper. Instead Queenslanders must register only a first preference to record a valid vote. They can, optionally, allocate a second, third, or forth etc. preference - but only if they wish.

This liberating move was a recommendation of the Electoral and Administrative Review Commission (EARC) as part of its review of our state electoral system.

In its report EARC said: "... under the current compulsory preferential system voters are being required to express views they may not have. Encouraging voters to express preferences is ultimately a matter for candidates and parties, not the electoral system."

It must be said there is nothing new about optional preferential voting in Queensland. It was first introduced in 1892 by the Griffith-McIlwraith government, and survived quite happily mainly because it did not drastically affect the result.

Between 1896 and 1935, optional preferential voting caused a different result to the commonly used first-past-the-post system in only six electorates in 16 elections.

However in 1938 the Protestant Labor Party, a breakaway Labor Party, went to the polls with the vexatious concern that Catholics were dominating the public service, yet represented only 19.2 per cent of the Queensland population!

The Labor Government in 1942 reintroduced first-past-the-post after the protestants and other independents won 5 seats at two general elections. It survived until the present compulsory preferential system was introduced in 1962.

This time, the Goss Government is not responding to any religious fervour. It is introducing optional preferential voting because Labor publicly committed itself to supporting all EARC electoral reforms, including EARC's recommended two-zonal system.

Yet all parties are apprehensive about the system's likely effect on marginal and even relatively safe seats. The Liberal and National parties worry optional preferential voting will reduce the flow of preferences between them; the Labor Party too is concerned about the possible fragmenting in their support in seats contested by greens and other independents.

Paradoxically, the smaller parties too are unconvinced the new system is in their interests - for example, in seats where they are second after the primary count, but could win after the allocation of preferences.

So is optional preferential voting about to shake up Queensland politics and deliver unexpected election results in many of our 89 seats?

Political commentator Malcolm Mackerras has been observing its effect on NSW elections in 1981, 1984, 1988, and 1991.

Mackerras says the system has delivered results very similar to those under compulsory preferential voting.

"There are plenty of cases where the Labor Party was leading on first preferences, and the Liberal and National parties were sufficiently able to exchange preferences to put the Labor candidate out," he said.

He says voters quickly latched onto the system. However, he suspects many NSW Liberal and Labor voters do not exercise their preferences beyond the first - except where how-to-vote cards recommend otherwise.

He says the major parties advocate for or against voters completing the entire ballot paper depending on the seat. Parties are more likely to recommend voters complete all preferences in seats where the ultimate contest may not be between the major parties.

Of course, Queensland is different to New South Wales in two distinct ways. First, the Liberal and National parties still participate in genuine three cornered contests, and secondly, the support for independents in New South Wales is significantly higher - 16.2 percent in 1991 compared to around four to five percent support in Queensland.

Here it will be the job of Electoral Commission of Queensland (ECQ) to alert and educate the public to the change.

Dr Glenn Rhodes, the manager of the ECQ's Research and Education Division, says the commission is planning a multi-media campaign - but its precise mix is still unknown.

"Quite clearly we've got a major job on our hands given the extensive reforms to the Queensland electoral system, and to the management and administration of elections," he said.

So the introduction and effect of the system in Queensland will be fascinating. Unfortunately, equally fascinating will be how long optional preferential voting survives, given all three major parties oppose it.

In April 1991, the Labor and National parties combined in state parliament to pass a motion to review it after the state election - a review ordered before the system has been tried.