Video and pictures have emerged showing some of the dry lightning strikes on Tasmania's east coast as the fires increase in dangerous weather conditions.

About 1,500 lightning strikes were recorded across the state overnight on Monday, with 500 reported between 9:00am and midday on Tuesday.

Lightning strike at Coles Bay on Tasmania's east coast. ( Supplied: George Hallett )

Tasmanian Fire Service (TFS) operations officer Mark Klop said the full impact of the strikes would not be known for at least a few days.

He said there could be more fires burning, which could develop further.

"At the moment we don't know, we've got air resources dedicated to going and looking at those, we're got fire crews as we speak," he said.

At 10:00pm (AEDT), the TFS said it was unsure how many fires were started by the lightning in the latest dry thunderstorm in the state's south.

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Firefighting crews were dispatched to investigate reports, but said they would not be able to confirm the number of incidents or water bomb-active fires until Wednesday morning.

There were 61 active fires reported across the state on the TFS website at 10:00pm, with fires at Wattle Grove, Great Pine Tier Central Plateau and Gell River listed at an advice level.

Senior forecaster Tim Bolden said the strikes were produced by thunderstorms which are not accompanied by rainfall.

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"We do see dry lightning, probably a couple of events a year, but having several days of dry lightning in a row is certainly unusual," he said.

A dry lightning strike started the Gell River bushfire in the state's south-west, which has burnt out about 20,000 hectares since late last month.

Efforts to fight the fire from the air are based at Bushy Park in the Derwent Valley and at Strathgordon.

Bushwalkers warned to leave

Walkers are being told to leave a popular water hole on the state's east coast because of a bushfire.

The fire at Douglas-Apsley National Park, near Bicheno, was reported just before 3:00pm.

The TFS issued an advice alert and was telling walkers and travellers to leave the water hole area.

The day use area, including the gorge and waterhole area, and the Leeaberra walking track were closed.

The TFS said two small fires caused by lightning were burning on Maria Island off the state's east coast.

Claudia Jenkins was on the island, and said she was advised by park rangers to leave.

"We saw a helicopter land, and then pick up a bucketful of water, and take it to the fire, and then a car drove back and stopped us and said, 'Start heading back'," she said.

The TFS said there had been no official evacuation advice for Maria Island.

Flames and smoke on button grass plains in the Tasmanian wilderness near Gell River. ( ABC News )

TFS looks at extra resources

Mr Klop said the TFS was looking at bringing in more crews from interstate, with a new rotation of the strike team from New South Wales hitting the ground on Tuesday.

"We're looking at our options, and again, prioritising any new fires that we may be made aware of in the landscape and also our needs for the Gell River fires," he said.

"So there is the possibility of additional resources requests but we haven't made that call yet."

In a statement, the TFS said resourcing had not been an issue.

Warmer temperatures are expected to continue through the week, with rain forecast for Friday and Saturday.

Forecasters said Friday would be the 26th day in a row above 20 degrees, breaking the record of 25 days set at the beginning of 2013.