BrisConnections, the operator of Brisbane's $4.8 billion Airport Link toll road, has finally called in the corporate paramedics after the majority of its bankers pulled the pin on restructuring proposals.

The toll-road operator's board today elected to place BrisConnections in the hands of voluntary administrators from McGrath Nicol, including Jamie Harris and John Cronin.

BrisConnections board decided in November to enter into "formal negotiations" with its lenders about "potential reconstruction options" after conceding that its debts may exceed the value of its assets.

But last night the board was told that the majority of its lenders was not "prepared to support these restructuring proposals".

BrisConnections said in a statement today that the directors were "unanimous in their decision" to appoint the administrators after "exhausting the alternatives available" to them.

A group of 10 banks including European heavyweights Deutsche Bank, BNP Paribas and Societe Generale lent about $3 billion to BrisConnections

The chairman, Trevor Rowe, said it was "disappointing that the board has had to reach this decision" as the Airport Link was a "world-class piece of transport infrastructure".

The tunnel will remain open to traffic as usual.

BrisConnections had long been expected to follow a similar path to the failed operators of toll-roads in Sydney such as the Lane Cove and Cross City tunnels, and Brisbane's Clem7 tunnel.

Traffic on the 6.7-kilometre toll road which connects Brisbane Airport to the central city has been half what Brisconnections was projecting it to be.

In November BrisConnections appointed corporate paramedics PPB Advisory to review its toll-road business. PPB had been looking at "current and anticipated traffic volumes, revenue, costs, forecast liquidity and BrisConnections' capital structure".