A storm system moving eastwards in the Coral Sea off Queensland is intensifying and expected to form into a cyclone overnight before hitting Norfolk Island, the Bureau of Meteorology (BOM) says.
The tropical low is developing strength and if a cyclone does form, it will be called Gretel.
BOM forecaster Alexander Majchrowski said he expected the system to hit Norfolk Island, off New South Wales, as a category two system early on Monday morning.
"As it passes through [Norfolk Island] and continues to move south, it will undergo extra tropical transition into a mid-latitude low pressure system," Mr Majchrowski said.
"The wind speeds will be equivalent to that of a category two tropical cyclone — winds in excess of 48 knots."
The BOM said it did not expect the system to significantly affect Queensland's weather, although a number of strong wind and gale warnings were in place for coastal waters.
"Today we have strong wind warnings south of Townsville, down to the Sunshine Coast, with a gale warning for the Great Barrier Reef offshore waters," Mr Majchrowski said.
"Tomorrow that focus will shift further south, with a strong wind warning for coastal waters south of Mackay and gale warnings for the Fraser Island coast, Gold Coast and Sunshine Coast."
A hazardous surf warning is expected to be issued from Monday for these waters due to an increase in swell generated by the system.
