Fire and Emergency is reminding people to take extra care when lighting fires after several planned vegetation burns got out of control in Southland recently.

It said the fire risk was rising in the region, where firefighters had to put out 21 vegetation fires over the past two months.

Southland community risk manager Delia Riley said most of the region was in an open fire season, but people needed to take precautions when lighting outdoor fires.

Some of the fires in recent months had been caused by burn piles setting fire to hedges or shelter belts, and in two cases nearby sheds caught fire.

"Piling up clippings close to the hedge you've just trimmed might be convenient but will spell trouble when you set the heap alight," Riley said.

In several other cases, fires had been lit in spite of forecast windy conditions or had reignited.

Burning embers could easily be blown long distances and start new fires, Riley said.

People should always log on to their website first to see whether there were any restrictions in place, and look at the weather forecast before reaching for the matches.

It was also important to have basic firefighting equipment like a hose ready and be prepared to keep a close watch on the fire, Riley said.

Old fires left unattended could also reignite in the wind, sometimes days or even weeks later, so these needed to be checked regularly and thoroughly doused with water if they showed any signs of heating up again, she said.

Three of October's fires in Southland were caused by old managed burn-offs reigniting in strong winds.