Mick Lynch, the Rail, Maritime and Transport (RMT) union boss has asked called on transport secretary Grant Shapps to “tone down the rhetoric and get on with his job” to "settle this dispute".
His remarks came after Mr Shapps accused the union of "damaging people's lives" after thousands of commuters were affected last week due to the biggest rail strike in the UK in more than three decades.
Train services were crippled again on Saturday due to another 24-hour strike by thousands of workers in a bitter dispute over jobs, pay and conditions.
Urging Mr Shapps to engage in talks, the union boss said: "So if Grant Shapps wants to be constructive that’s what he can do. He needs to tone down the rhetoric and get on with his job, which is to settle this dispute."
Last week's strikes were called as part of a dispute over pay and conditions on the railways, after the government asked train operating companies to find savings through “modernisation”.
