Bernard Collaery (left) and Labor MP Luke Gosling (right) (Images: AAP)

Labor MP Luke Gosling has called on Attorney-General Christian Porter to explain why his prosecution of Witness K and Bernard Collaery is in the public interest, and says the government has missed an opportunity to put its poor treatment of Timor-Leste in the past.

The Northern Territory MP has extensive links with the country after serving there while in the ADF and spending several years there running an NGO.

Earlier in the year, Gosling criticised Porter's attempt to prosecute K and Collaery in a secret trial, but now says Porter must make up for his failure to explain why he is pursuing the two men.