Britain's RMT rail workers' trade union said on Wednesday it will ask its members to vote on an improved pay offer from rail infrastructure group Network Rail, after suspending plans for a strike.

The new pay offer from Network Rail, the public sector group which owns and operates thousands of miles of tracks, bridges and tunnels, amounts to a rise of 14.4% for the lowest paid grades of workers to 9.2% for the highest paid, the RMT said.

The trade union said it was not making a recommendation on how to vote in the referendum, which will start on March 9 and end on March 20.

"We will continue our campaign for a negotiated settlement on all aspects of the railway dispute," RMT General Secretary Mick Lynch said.

On Tuesday the union suspended all strike action involving Network Rail staff after the new pay offer in the long-running dispute that has led to months of disruptive transport strikes.

A separate pay dispute between RMT members and more than a dozen train operators remains unresolved.

The Rail Delivery Group (RDG), which represents the train companies, said it had invited the RMT to hold talks on Thursday.

But the RMT said this offer of talks had been made on the condition the strikes were suspended and while it was open to discussions, planned strike action on March 16 and 18 would go ahead.

"Meaningful progress can only be made if they remove the threat of strikes hanging over our passengers before it is too late to avoid disruption," an RDG spokesperson said. "We urge the RMT leadership to engage with us in good faith and resolve this dispute."

(Reporting by William James; Writing by Sachin Ravikumar and Kylie MacLellan; Editing by Daniel Wallis)