Two men have been arrested over the death of Melbourne teen Cayleb Hough, whose body was found in a shallow mineshaft.

The Chelsea Heights teen's remains were discovered in the Lerderderg State Park in Bacchus Marsh on March 10 and the homicide squad began investigating.

The 17-year-old went missing on December 20 last year after he was seen travelling in a car with a man.

Victoria Police on Thursday revealed a 36-year-old man was arrested at a house in Collingwood on Wednesday.

Another man, 28, was arrested on Tuesday at a property in Gellibrand, in the Otway Ranges, and interviewed before being released pending further inquiries.

A vehicle was seized at the Gellibrand property and is being examined by police.

The vehicle is not the same one that Cayleb Hough was last seen in - which was found at a Melbourne car park in January.

It remains unclear whether the teenager died in the park or elsewhere.

Cayleb's family will farewell the 17-year-old at a funeral service on Friday.

WHAT HAPPENED TO TEEN CAYLEB HOUGH?

* December 20 - last seen in a car driven by another male; doesn't use mobile, social media or bank account again

* January 15 - police search for the bright blue Ford Falcon XR6 sedan and ask the driver to come forward

* January 16 - car found in the car park of Crown Casino and undergoes forensic tests

* March 10 - human remains found near Seerey Track at Lerderderg State Park

* April 12 - police confirm remains belong to Cayleb Hough

* April 19 - 28-year-old arrested and a vehicle seized in southwest Victoria; man interviewed and released

* April 20 - a man, 36, is arrested in Collingwood

© AAP 2016