A grass fire at Hall has been extinguished this afternoon, but the Community Fire Unit remains in place to monitor conditions.

ACT Rural Fire Service were alerted to the fire at Hall Showground at about 1.30pm.

Ten units were sent to deal with the fire which was quickly brought under control, and measured about 10m by 10m.

The blaze is now out but the cause is unclear.

Meantime staff from TAMS have been asked to report suspicious behaviour, as they go about their work today.

This includes city rangers, ACTION bus drivers and ACT Parks and Conservation staff.

A total fire ban remains in place today in the ACT.