Labor’s shambolic border protection approach has seen budget assumptions blown out of the water, according to David Tune, secretary of the Department of Finance and Deregulation.

Responding to questioning by Senator Scott Ryan in the Senate Finance and Public Administration Committee, Mr Tune said his department, together with the Department of Immigration and Citizenship, had developed a way of calculating the cost of boat arrivals.

However, with the massive influx of arrivals since the Labor Government’s dismantling of successful Coalition policies, the funding model has fallen over.

Asked whether the department’s assumptions about the cost of boat arrivals had been useful, Mr Tune replied: “I’d say we haven’t been all that close to the mark. There’s been constant upward movements.”

Pushed by Senator Ryan as to whether the Department of Finance and Deregulation had underestimated the asylum seeker blow-out, Mr Tune replied “I think it’s fair to say”.

Senator Ryan, deputy chair of the Senate Finance and Public Administration Committee, said “Mr Tune’s refreshing honesty has confirmed what we’ve known all along: Labor’s asylum seeker failures are having a serious impact on the budget bottom line.”

“We will have to wait until MYEFO to see just how much more Julia Gillard and Chris Bowen’s failed asylum seeker policies have cost,” Senator Ryan said.

In 2012, so far 12,544 asylum seekers have arrived on our shores, an average of over 1,300 boat arrivals per month.

A quarter of the way through the 2012-13 year, more people had arrived on illegal boats than the Gillard Government had budgeted for the entire financial year.

“The Coalition has a tried and tested policy to stop the boats: offshore processing, temporary protection visas and turning back the boats when it is safe to do so,” Senator Ryan said.