Pair 'lucky' to be alive after falling down Victorian cliff face

One man has suffered critical injuries and another is in a serious condition after they plunged 10 metres while abseiling at Victoria's Phillip Island, south-east of Melbourne.

The pair were about halfway down the rock face at Cape Woolamai when they ran into trouble, plunging the remaining 10 metres onto rocks below near the waterline.

A third co-worker abseiled to the bottom and called emergency services just before midday.

Paramedics rushed to the scene at about 1.45pm, where they found the injured pair stuck at the bottom of a cliff, unable to move.

Footage showed rescue workers desperately trying to keep the pair out of the slowly rising water as the tide came in.

Water police and the Coast Guard rescued the pair and brought them to shore at San Remo.

The pair was then flown to the Alfred Hospital by helicopter.

The third uninjured man spoke to 9NEWS off-camera and said he did not know the cause of the "ropes failure".

Police told 9NEWS that the men were lucky to survive as it could have been a much worse outcome.

"We were very lucky that the weather is as calm as it is today to get boats in there, normally that'd be very hard and we would be still doing a rope rescue as we speak," Sgt. Victor Velthuis said.

Both men suffered multiple injuries, with a man aged in his 50s in a critical condition, while the second man is in a serious condition.

The three men were contract workers for Parks Victoria, hired to remove weeds at Phillip Island.

Worksafe Victoria has launched an investigation into the accident.