The delay in reopening the Olympic Stadium has been branded "a farce" by the chairman of UK Athletics.
The London Legacy Development Corporation (LLDC) said the east London stadium would not reopen until 2015 or possibly in summer 2016.
UK Athletics chairman Ed Warner, who expected it to open in 2014, said he had been stunned to learn of the delay.
An LLDC spokeswoman said when the stadium opened would depend on which bid for its future use was successful.
LLDC chief executive Dennis Hone told the London Assembly last week that a 2014 reopening was "completely out, it would be August 2015 at the absolute earliest and possibly August 2016".
UK Athletics had planned events such as Diamond League meetings, trials and school competitions at the stadium in Stratford.
Mr Warner said: "My biggest concern is that we have some major events planned for that stadium and we thought they were going to be from the summer of 2014 onwards.
"All of the legacy use was scheduled to start in two years' time and now it might be four years' time, which strikes me as ludicrous and to be a paralysis of decision-making which I hope the mayor is going to cut through.
"I wouldn't say this is a Whitehall farce but this is fast becoming a Stratford farce.
"We want to lock into the legacy of the Games while people still remember the Mobot, Greg Rutherford, Jonnie Peacock and David Weir," he added.
Grand prix circuit
"Let's have a bit of imagination here and let's have a decision - we want one, West Ham want one and we all want it open as soon as possible."
West Ham United, which won the now-disbanded process to move to the stadium after the London 2012 Games, is one of those bidding to use the stadium in future.
The UCFB College of Football Business and Leyton Orient Football Club have also submitted applications, along with Intelligent Transport Services, which has tabled plans for a Formula 1 grand prix circuit.
A decision is expected by 5 December.