Labor has retained the seat of Inala but is in danger of losing Ipswich West following two by-elections that give new premier Steven Miles a gauge of his chances in the upcoming state election.
Counting continued on Saturday night in the Labor heartland seats but on early projections ABC chief elections analyst Antony Green called Labor to hold Inala, which was held by former premier Annastacia Palaszczuk.
On projections based on preference counts, Labor's Margie Nightingale had 55.5 per cent with the Liberal National's Trang Yen on 44.5 per cent, but the swing to the LNP was moe than 20 per cent.
But an LNP win looked to be on the cards in Ipswich West where the early preference count was 53.3 per cent for the LNP's Darren Zanow, with Labor's Wendy Bourne on 46.7 per cent - a swing to the LNP of almost 18 per cent.
The Queensland state election is set to be held in October, with an opinion poll released on Friday indicating Mr Miles faces defeat.
The premier's rivals, the Liberal National Party, led the two-party preferred vote 54 per cent to 46 per cent in the poll published by News Corp.
Mr Miles told reporters he expected swings against the government "in the double digits".
"It's usual to expect swings against governments in by-elections," he told reporters at Ipswich High School on Saturday morning after polling booths opened.
"That's what we nearly always see and so that's what we're expecting here."
That was echoed by Prime Minister Anthony Albanese, who told Nine's Today program he also expected a swing away from the Labor government.
However, Opposition Leader David Crisafulli warned supporters to be "realistic" because Labor held Ipswich West by 14.3 per cent and Inala by 28.2 per cent.
"If there is a swing towards the LNP of anything north of about three to four per cent there will be rumblings in the Labor Party," he told reporters in Brassall on Saturday.
About a third of voters had already made up their minds and submitted their decision before election day across both seats, according to the Queensland Electoral Commission.
Contested for the first time in 1992, the Inala electorate was initially represented by Ms Palaszczuk's father Henry.
He went on to become a senior minister before being succeeded by his daughter who resigned in December.
It's considered Queensland's safest Labor seat but Ms Palaszczuk took no chances on Saturday, stopping by a polling booth in the electorate to show her support.
An Ipswich West by-election was triggered by Labor MP Jim Madden departing in January.
He will run for Ipswich council election in Saturday's Queensland local government elections.
Since 1992, the average swing against Labor at by-elections when they are in government is five per cent.
