A total fire ban has been declared in the ACT with temperatures in Canberra expected to reach into the mid-30s today.

The Bureau of Meteorology is forecasting hot and windy conditions with a top temperature of 36 degrees. The hot weather is expected to last all week.

The ACT Emergency Services Agency is reminding people that no fire may be lit in the open during a total fire ban.

Anyone convicted of lighting a fire during the ban may face criminal charges.

Several nature reserves and roads will be closed today as a precaution.

Tidbinbilla Nature Reserve, Googong foreshore, Lower Molonglo River Corridor and parts of Namadgi National Park are off limits.

Canberra Nature Park and pine forest areas will also be closed after 11:00am AEDT.

All gas barbeques have been turned off but visitors can still use electric barbeques at the Cotter, Casuarina Sands, Pine Island and in Canberra's urban parks.

Meanwhile, fire fighters have been kept busy putting out several grass and rubbish fires in Canberra's south early this morning.

Police are investigating whether the fires were deliberately lit.