Infrastructure investor Infratil today said its annual profit had fallen by 68 per cent due to losses incurred by its European airport investments.

The company posted a net profit after tax of $7.7 million in the year to March 31, compared with $23.7 million in the same period last year.

Last year's result was boosted by investment realisations of $22.7 million compared with $200,000 this year.

Infratil owns 100 per cent of Glasgow Prestwick Airport in Scotland, Kent International Airport in England, and Lubeck Airport in Germany, as well as a large stake in Wellington Airport.

Ebitda (earnings before interest, tax and depreciation) for the European airports in the year to March 31 were $1.7 million, compared with $10.6 million in the previous year.

A fully imputed final dividend of 7.5 cents per share - up 36 per cent on last year - will be paid on June 12.

During the year Infratil has paid $252 million for Stagecoach Plc's bus services in Auckland and Wellington and Fullers Ferries.

It also bought a power station in South Australia, and made additional incremental investments at Wellington Airport, TrustPower and in Victoria Electricity.

TrustPower contributed $28.6 million to Infratil over the year, up from $25.7 million the previous year.

The earnings contribution (after minority interests) from Wellington Airport was $24.0 million, from $23.7 million last year -- a result chairman David Newman said was "satisfactory in the context of weak passenger activity and operating cost pressures".

Over the year, Wellington Airport invested $25.8 million in new facilities.

Mr Newman said a cautious approach was being taken in progressing further development.

"Air New Zealand, Wellington Airport's main customer, has announced it will significantly reduce capacity if it gains regulatory approval to form a cartel on the Tasman routes with its main competitor Qantas."

Mr Newman said this year had been one of considerable progress for Infratil and it was in a strong position to continue growth through the year.

Shares in Infratil fell 8c to $4.40 today, having ranged between $3.36 and $4.54 over the past 12 months.