UPDATED 1.30PM: Police are appealing for the public's help in the investigation into a double homicide in Dunedin.

The bodies of Anastasia Margaret Neve, 39, and David Ian Clarke, 49, were found inside the Wesley St, South Dunedin, property, after last week's fire.

The incident was originally believed to be a fatal fire but today police say they were dead before the blaze broke out.

Detective inspector Steve Woods stated that it's a complex investigation complicated by the fire damage, but asking for anyone who has information about car, motorbike, or pedestrian activity in the vicinity of Wesley Street on the 22nd of January to get in touch with police.

A 46-year-old man has appeared in the Dunedin District Court today charged with arson in relation to the fire.

He's been granted name suppression, but no one has yet been charged in relation to the deaths.

Witnesses saw heat from flames smashing windows and smoke billowing from the roof of the one-storey wooden property in Wesley St about 5.10am on January 22.

Neighbour Dylan Ryall said he went outside as soon as he was alerted to the fire by his step-mother.

"First we saw smoke coming off the roof, then the front window ... actually blew out - flames were coming out the side of it.''