Fire crews battling townhouse blaze in northern Sydney suburb of Dundas

A man is being treated for smoke inhalation after a home caught fire in Sydney's north.

Fire crews and police were called to the two-level townhouse on Rippon St in Dundas this morning.

Part of the roof of the house has collapsed, while a thick column of smoke pours into the sky.

Emergency calls were made shortly after 7.30am, with six trucks deployed to the scene.

The fire is believed to have started on the first level of the two-level house, before extending up into the roofing.

All occupants of the house are understood to be safe.