The time asylum seekers spend in Australian detention centres has blown out to a record high under the Turnbull government, leaving men, women and children languishing behind wire, facing an uncertain future.

The latest statistics from the Department of Immigration and Border Protection show that in December, people in onshore immigration detention had been there for an average 445 days. In November, the figure was 446 days.

The average detention period has increased steadily since May last year and is now the longest since the government took power. It is more than double the 200-day wait four years ago under the Labor government.