Australian superannuation funds are the fastest growing funds in the world, according to a Watson Wyatt survey.

While the superannuation funds account for only 2 per cent of total assets of the world's largest 300 pension funds, this has more than doubled since last year, pushing three more funds into the rankings.

The funds that are ranked in the top 300 largest global pension funds include Future Fund (66), State Super (89), AustralianSuper (121), Unisuper(124), QSuper (143), ARIA (186), First State Super (230) and REST (238).

The three new funds adding to the line-up are HESTA (260), Cbus (275) and Telstra Super (295).

Collectively, all these funds manage more than $260 billion in funds under management.

The Future Fund jumped up 122 places, largely as a result of receiving contributions from the Commonwealth Government.

The strongly performing Australian dollar contributed to the increase in the size of the funds, according to the report.

Watson Wyatt head of investment consulting practice Graeme Miller said compulsory superannuation also spurred this growth.

"The 9 per cent superannuation guarantee contributions, coupled with attractive tax benefits and a healthy level of competition between the commercial and not-for-profit sectors, have ensured that our superannuation industry has flourished to become the fastest growing in the world," Miller said.

Retail funds were not part of the global survey.