Australia's worst locust plague in 70 years has marched into metropolitan Melbourne as federal and state authorities met to consider their plan of attack.

Federal Agriculture Minister Joe Ludwig today met with ministers and officials from NSW, South Australia, Victoria and Queensland to discuss the response to the swarms.

Senator Ludwig said the response so far had been "extremely efficient", but with the pests taking to the wing the time had come to discuss realistic approaches to controlling the swarms.

There had been an increase in reports of fledgling or young adult locusts, with swarms even spotted in Melbourne, he said.

"There has been a sudden influx of locusts into parts of the Melbourne metropolitan area," Senator Ludwig said in a statement.

"More localised movement will occur in all affected areas during the coming weeks, before significant long-distance swarm migration is likely to occur."

Spraying swarms was "inefficient, less effective and costly", and potentially dangerous if done from the air, Senator Ludwig said.

"However, we recognise the urgency in tackling this problem and treatment of swarms will be considered in extreme circumstances," he said.

"It is absolutely critical that landholders continue to monitor locust outbreaks because treatment on the ground before locusts swarm is the most effective tool."