A plan by the opposition to force government workers back to the office full time could affect millions, a trade union grouping says, with the issue set to be a prominent one in the upcoming federal election.

The Liberal party has said if elected, it would bar hundreds of thousands of government employees from working from home, except for exceptional circumstances.

But the resulting increased traffic congestion would have a knock-on effect on millions more workers, said the Australian Council of Trade Unions, whose 38 members together represent almost 2 million workers.

"Forcing hundreds of thousands of workers back on the roads will mean less time with kids and more time in traffic," said the grouping's chief executive, Michele O’Neil.

The Liberals' pledge puts them at odds with the Labor Party in campaigning for the election that must be held by May, at which the high cost of living tops voters' concerns.

Prime Minister Anthony Albanese said allowing employees to work remotely had allowed workers to spend more time with their families, as well as save on commuting.

"We know that working from home has had a range of advantages," he said, calling the opposition "out of touch" for the plan to curb it for government workers.

Labor and the coalition are near-deadlocked in the latest opinion polls, with swing seats on the outskirts of major cities – among the most exposed to the high cost of living – likely to be crucial.

Labor has seen a modest bounce in outer metropolitan areas in recent weeks, in part due to the Liberal Party's proposed curbs on working from home.