Agency workers could be called in to replace striking rail staff, according to a report.
Labour’s Tony Blair introduced a restriction on using agency staff to stand-in for striking workers when he was prime minister.
But Transport Secretary Grant Shapps told The Sunday Telegraph that ministers are looking at ways to repeal this.
It comes as the Rail, Maritime and Transport Workers’ union prepares to strike on 21, 23, and 25 June in a dispute over pay and redundancies.
More than 40,000 staff at Network Rail and 13 train operators are expected to walk off the job, in what the union has described as the “biggest rail strike in modern history”.
Ministers are drawing up legal changes that could take effect “during this particular dispute” if it continues, to prevent the public from being “held to ransom”.
Last month it was reported that the government also wants new laws requiring a minimum number of rail staff to work during a strike.
This would require an Act of Parliament, so would be a slower process than repealing the law banning agency staff from filling in for striking workers.
Mr Shapps told the newspaper: “I can’t over-stress our determination to get the right outcome for the travelling public in the end on this, even if the unions insist on putting the country through considerable pain in the meantime.”
He said any intervention was unlikely to apply to the three strikes already announced but added: “If this action continues, then these further measures certainly would come in during this particular dispute, if it can’t be resolved”.
Mr Shapps said: “When you look at the people who work on the railways, many of them have done a phenomenal job.
“They are being led by union barons, in some cases very extreme Marxists, who are determined to turn this into some sort of fight, as they see it, with a Tory government.”