A decision is due over whether a 72-hour Tube strike called in a row over safety is going to go ahead.
Unions have called off a 72-hour Tube strike planned for next week.
Members of the Rail Maritime and Transport (RMT) union and the Transport Salaried Staffs Association are due to walk out from 1830 BST on Sunday.
Members of the Rail Maritime and Transport (RMT) union and the Transport Salaried Staffs Association were due to walk out from 1830 BST on Sunday.
They have voted for industrial action in protest at ticket office closures and the use of agency employees.
Talks have been ongoing since they voted for industrial action in protest at ticket office closures and the use of agency employees.
But recent talks between union leaders and London Underground (LU) managers are said to have made good progress.
London Underground (LU) had said the issue had nothing to do with safety and no jobs were at risk.
'Confusion and chaos'
Union leaders had warned that station office closures, the use of agency staff and other changes represented a danger to passengers and staff.
London Underground said on Monday the issue had nothing to do with safety and no jobs were at risk.
A RMT spokesperson said: "A meeting is being held between union representatives at London Underground and the council of executives to consider an offer made by LU and a decision is due to be made this afternoon."
Tens of thousands of supporters of Cardiff City and Barnsley football clubs attending this Sunday's FA Cup semi-final at Wembley Stadium would be affected by the strike and were warned of "confusion and chaos" as they tried to find alternative ways of returning home after the game.
