Laboratory operator Campbell Brothers Ltd has increased its first half profit forecasts due to better than expected trading.

The company now expects an underlying net profit of $100 million for the six months to September 30, up from its previously advised figure of between $90 million and $95 million.

If these expectations are met, first half net profit will be up by 51 per cent on the previous corresponding period.

Campbell Brothers offers laboratory services and makes cleaning and chemical products.

It said its laboratories are experiencing record sample volumes in the fiscal year to date, with its North and South America and Africa operations particularly strong. These levels of activity are expected to be maintained until at least December, Campbell Brothers said.

Also of benefit to the company has been a fall in the value of the Australian dollar.

Campbell Brothers shares were up $1.86, or 4.8 per cent, at $40.90 at 1123 AEST.