By Lucy Craymer

WELLINGTON (Reuters) -New Zealand police said they had arrested and charged a man with two counts of arson on Thursday after a hostel fire in the capital, Wellington, killed at least six people this week.

A blaze broke out on the top floor of the Loafers Lodge in the suburb of Newtown in the early hours of Tuesday, causing major structural damage that hampered efforts to get inside.

In a statement posted on Facebook, police said they could not rule out charging the man with further offences.

"The investigation into the fire is ongoing and police have not ruled out further, more serious charges in relation to the deaths at the scene," they said in the statement.

The authorities opened a homicide inquiry on Wednesday after saying that arson was suspected.

Inspector Dion Bennett, acting Wellington district commander, said a reconnaissance team had conducted an initial preparatory examination of the building and expected to be able to bring out two bodies on Thursday and a further two on Friday.

"The scene examination is expected to take several days," Bennett said, adding that police did not know how many people had died in the fire.

(Reporting by Lucy Craymer and Akriti Sharma; Editing by Jamie Freed and Gareth Jones)