The latest market downturn is seeing margin lending borrowers squeezed for the second time in 12 months.

According to Macquarie Investment Lending head of sales and marketing Peter van der Westhuyzen, the number of margin calls has increased over the last couple of weeks, but as a percentage of the total number of clients in margin lending they continue to fall.

"If you have a bigger book size you are expecting more margin calls," van der Westhuyzen said.

According to figures from the Reserve Bank of Australia, the average number of margin call per 1000 clients in the September quarter was around one per cent.

This represented a large jump form the previous quarter, at 0.25 per cent, but nowhere near the high, registered in the September quarter of 2001, at over eight per cent.

Van der Westhuyzen said that two strong market retracements in a 12-month period is very uncommon.

"It's a fairly unique situation, and we are counselling advisers that it is really about keeping people informed, and on that front we are making as much real time information as possible available to them," he said.

"We are saying to advisers that while margin calls are quite often viewed in a negative light, they can be used as a quite timely risk management tool."  

According to Van der Westhuyzen, while the level of margin calls hasn't yet reached those of August, the bank is mapping the trend closely.

"While we are only halfway through the month it is actually tracking below August and if the numbers continue this way we will end up below," he said.