The struggling domestic tourism industry, cheap international flights and increased Tasmanian air services are being blamed for the 16 per cent drop in outbound Spirit passengers for 2011-12.

Tourism Tasmania's annual Tasmanian Visitor Survey is based on an exit sample of 9000 visitors.

It claims the survey is the most reliable source of data on visitors to the state. 

It showed 22,000 fewer people caught a ride on the Spirit as it left Devonport last financial year. 

Overall 112,400 visitors used the ferry service to depart Tasmania. 

At the same time Devonport Airport enjoyed a 19 per cent jump in the number of passengers using its terminal to leave Tasmania _ a boost of 4500 flyers.  

The survey showed Launceston Airport suffered a drop of 7 per cent in the number of visitors departing from there although the port's own figures show passenger numbers were down by only 2 per cent overall. 

Visitors to Tasmania in 2011-12 dropped 4 per cent in total.

A Spirit spokeswoman said it was ``dangerous'' to look at one year in isolation but conceded it had been a tough period for the company. 

``A review of national figures reveals that domestic tourism was impacted in all parts of Australia as people chose to holiday overseas given the strong Australian dollar and the availability of cheap international airfares,'' she said.  

``Though it is very early days, there are some good signs in terms of passenger numbers for 2012-13.''

Infrastructure Minister David O'Byrne said the Spirit had steadily grown its passenger numbers and customer satisfaction levels in the past five years. 

``The government has strong confidence in the board and management of TT-Line, which continues to innovate and improve the ferry service in challenging tourism conditions,'' he said. 

Tourism Tasmania said air travel was only down by 2 per cent compared with the 16 per cent reduction in seafaring visitors. 

``That indicates the strong reliance that Tasmania has on air access to the state,'' Tourism Tasmania's Adam Sproule said.