The incident happened on the road in Buriton near the B2070 turn off and the northbound carriageway was completely blocked initially.
Lane one remains closed and there are delays stretching back towards Clanfield.
Hampshire County Council’s traffic account ROMANSE is warning of 40 minute queues.
In a tweet it said: ‘A3 Buriton - Lane 1 remains CLOSED northbound after earlier vehicle fire near B2070 turn off, delays remain of approx 40 minutes heading back towards Clanfield.’
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