After weeks of speculation about his future, Northern Territory's police commissioner Jamie Chalker has retired from his post, six months before his contract was due to expire. 

The announcement comes a day before Mr Chalker was due to file his evidence in a Supreme Court case that he had brought against the Northern Territory government. 

The case could have seen Chief Minister Natasha Fyles and Police Minister Kate Worden cross-examined in court. 

The former police commissioner had reportedly been asked to resign by the NT government, but just last month, he had said he intended to stay in the role for years to come. 

Mr Chalker hired a high-profile legal team who launched Supreme Court action against the government. 

With a confidential settlement agreement now in place, the details of Mr Chalker's agreement with the NT government will be a closely guarded secret that all those involved will likely be legally compelled to keep to themselves.

A detailed breakdown is accessible here.