Termination for Delay
If time is not of the essence you can still sue if there is some sort of loss involved, but you cannot not terminate. A party wishing to terminate anyhow can do so by giving notice of their intention. If you give notice to the counter-party after an unreasonable delay, specifying reasonable time for completion, then time becomes of the essence. Failure to meet the notice period creates the right to terminate.
An example of termination after notice is found in Luarinda v Capalaba Park Shopping Centre. Laurinda, a commercial tenant, took occupancy in a shopping centre in Brisbane, but the centre management failed to register the lease. That meant there was nothing but an equitable lease. (Meaning they had rights from having paid, but not a full leasehold estate). The tenant eventually engaged solicitors who gave notice to complete the registration in 14 days. But registration would take longer than that.
The court ruled that there is a difference between a party intending to carry out a contract only ‘if and when it suits him,’ and a party being willing to carry out a contract ’as it suits him to do it and when its suits him to do it.’...
ORDER FOR FULL TEXT.
 Luarinda Pty Limited v Capalaba Park Shopping Centre Pty Limited  166 CLR 623.