About an hour after union representatives confirmed planned strikes for next week would likely go ahead, Premier Dominic Perrottet on Friday announced travel would be free from Monday to Friday on Sydney Trains services.

RTBU Secretary Alex Classens said one of the only ways to prevent slashing rail services to 30 per cent on Monday and Friday was for the government to make fares free for commuters on those days.

"We've been going on for way too long," Mr Perrottet said.

"Providing free travel for the week will ensure that industrial action does not occur."

Mr Perrottet described discussions between the sides as constructive and said he hoped the dispute would be resolved by the end of next week.

The union had previously revealed plans to open Opal gates for all customers but said it was forced to abandon the plan due to actions launched by the government in the Federal Court at taxpayers' expense.

AAP