New Zealanders are being advised to keep an eye on their retirement savings

The Super Fund is performing worse than forecast.

Treasury's latest Crown accounts show the 56-billion dollar fund's poorer than expected result has added 2.2 billion dollars to the Government's net debt in the 10 months to April.

But it is still doing well, delivering a 10-percent return this year before tax and after costs.

Superannuation expert Jonathan Eriksen says people should be actively involved in their savings.

He says it means investors can pick better stocks, but they have to pick the right one - and that's easier said than done.