Australian car manufacturers posted their best-ever monthly sales figures last month.

The Federal Chamber of Automotive Industries explained that 97,212 new cars and trucks were sold in June, which is up 5.6 per cent on June last year, the previous best-ever month.

The record month also helped yearly first half sales to climb to an all-time high of 473,516, which is up 6.3 per cent year-on-year.

Toyota returned the strongest sales figures for June, selling 22,116 vehicles to finish ahead of Holden on 17,502 and Ford on 13,314.

Improving Australian car sales implies an increase in demand for platinum and palladium from Australian manufacturers to be used in autocatalysts to control harmful exhaust emissions.

FCAI chief executive Peter Sturrock said that while the surge in new car sales represented a "firm platform of demand", a number of factors could limit sales slightly in the second half of the year.

"Manufacturers and distributors are now planning for continued activity at this level," Mr Sturrock stated.

"Traditionally, sales demand in the second half of the year runs marginally above that of the first half."

However, he added: "But demand has become so strong and so constant that last year the split between the first and second half of the year was only 2.5 per cent."